Crash on render if Render Layers image output is connected to a Viewer node AND anything other than a Group Output's first Image item #27

New Issue

Triager-bot · 2026-04-12T17:10:08Z

Triager-bot commented

2026-04-12 17:10:08 +00:00

Original bug report: https://projects.blender.org/blender/blender/issues/157183

System Information
Operating system: Windows-10-10.0.19045-SP0 64 Bits
Graphics card: NVIDIA GeForce RTX 3060 NVIDIA Corporation NVIDIA 595.97 Vulkan Backend

Blender Version
Broken: version: 5.1.0, branch: blender-v5.1-release, commit date: 2026-03-16 18:50, hash: adfe2921d5f3
Worked: 5.0.1

Short description of error
Blender will crash if the user attempts to render when the Image output of a Render Layers node is connected to both a Viewer node and a Group Output node, but only if the image is connected to anything other than the Group Output's first Image item. This happens in both Cycles and Eevee. There are various combinations that don't cause a crash (e.g. if the Viewer node isn't connected at all). It needs connections to both the Viewer node and to the Group Output's 2nd, 3rd, or 4th (etc.) input, just not the first Image item.

Exact steps for others to reproduce the error

From an empty scene open up a Compositor editor.
Starting from a completely blank slate, create a Render Layers node, Viewer node and a Group Output node.
Connect the Image output from the Render Layers node to the Viewer node.
Connect the Image output from the Render Layers node to a 2nd Image item slot in the Group Output node (by dragging onto the new socket input).
Hit render. It will either crash (getting stuck on 100% after the render job is attempting to complete the compositing phase), or if the user manages to cancel before it freezes it will get stuck in the "Cancelling..." phase and the crash will happen when the user attempts to close Blender.

Original bug report: https://projects.blender.org/blender/blender/issues/157183 **System Information** Operating system: Windows-10-10.0.19045-SP0 64 Bits Graphics card: NVIDIA GeForce RTX 3060 NVIDIA Corporation NVIDIA 595.97 Vulkan Backend **Blender Version** Broken: version: 5.1.0, branch: blender-v5.1-release, commit date: 2026-03-16 18:50, hash: `adfe2921d5f3` Worked: 5.0.1 **Short description of error** Blender will crash if the user attempts to render when the Image output of a Render Layers node is connected to both a Viewer node and a Group Output node, but only if the image is connected to anything other than the Group Output's first Image item. This happens in both Cycles and Eevee. There are various combinations that don't cause a crash (e.g. if the Viewer node isn't connected at all). It needs connections to both the Viewer node and to the Group Output's 2nd, 3rd, or 4th (etc.) input, just not the first Image item. **Exact steps for others to reproduce the error** 1. From an empty scene open up a Compositor editor. 2. Starting from a completely blank slate, create a Render Layers node, Viewer node and a Group Output node. 3. Connect the Image output from the Render Layers node to the Viewer node. 4. Connect the Image output from the Render Layers node to a 2nd Image item slot in the Group Output node (by dragging onto the new socket input). 5. Hit render. It will either crash (getting stuck on 100% after the render job is attempting to complete the compositing phase), or if the user manages to cancel before it freezes it will get stuck in the "Cancelling..." phase and the crash will happen when the user attempts to close Blender.

output_group_3_no_crash.jpg

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output_group_4_no_crash.jpg

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output_group_2_no_crash.jpg

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output_group_1_no_crash.jpg

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Triager-bot added the

Status

Needs review

label 2026-04-12 17:10:08 +00:00

Triager-bot commented

2026-04-12 17:10:19 +00:00

Report is clear

LLM Reasoning

Got it, let's see. The bug report has a clear title, a short description that explains the condition (Render Layers output connected to Viewer AND Group Output not first item), and exact steps to reproduce. The steps are numbered and detailed. So the clarity is good. So the answer should be Yes.

JSON Data

{
"llm_judgement": true,
"processing_time": 5.939744000000001
}

### Report is clear <details> <summary>LLM Reasoning</summary> Got it, let's see. The bug report has a clear title, a short description that explains the condition (Render Layers output connected to Viewer AND Group Output not first item), and exact steps to reproduce. The steps are numbered and detailed. So the clarity is good. So the answer should be Yes. </details> <details> <summary>JSON Data</summary> { "llm_judgement": true, "processing_time": 5.939744000000001 } </details>

👍 1

Triager-bot commented

2026-04-12 17:10:30 +00:00

Report is specific

LLM Reasoning

Got it, let's analyze this bug report. The question is whether it's specific or generic.

First, let's recall the definitions: Specific is about a particular issue (like crashing with a specific setup), Generic is vague (like just "crashing while rendering").

Looking at the bug report: It describes a very precise scenario—connecting Render Layers to Viewer and Group Output's 2nd+ input causes crash. The steps are exact, and it specifies which connections lead to the issue. So this is a specific issue because it's about a particular combination of node connections leading to a crash.

So the answer should be 'Specific'.

JSON Data

{
"llm_judgement": true,
"processing_time": 10.055831
}

### Report is specific <details> <summary>LLM Reasoning</summary> Got it, let's analyze this bug report. The question is whether it's specific or generic. First, let's recall the definitions: Specific is about a particular issue (like crashing with a specific setup), Generic is vague (like just "crashing while rendering"). Looking at the bug report: It describes a very precise scenario—connecting Render Layers to Viewer and Group Output's 2nd+ input causes crash. The steps are exact, and it specifies which connections lead to the issue. So this is a specific issue because it's about a particular combination of node connections leading to a crash. So the answer should be 'Specific'. </details> <details> <summary>JSON Data</summary> { "llm_judgement": true, "processing_time": 10.055831 } </details>

👍 1

Triager-bot commented

2026-04-12 17:10:44 +00:00

Report flagged as NOT a duplicate by LLM

Vulkan: Crash when image connected to transform compositor node

https://projects.blender.org/blender/blender/issues/155302

System Information
Operating system:window 10
Graphics card:3060rtx

Blender Version
Broken: 4.5, 5.1
Worked: OpenGL backend

Short Description

while using compositor transform node blender kept crashing dont know the cause
i have provided the blend file and the image i dont know if image has any relation to it tho
edit: also provided a obs video if blender does not crash on your side

Steps to Reproduce

Open attached scene
Load provided image inside the image node (should crash here. If not, do next step)
Render image

LLM Reasoning

Got it, let's analyze these two bug reports. First, look at the descriptions and steps.

Bug report 1 is about a crash when connecting Render Layers to Viewer AND Group Output's non-first input. The steps involve specific nodes: Render Layers, Viewer, Group Output, with connections to Viewer and a non-first slot in Group Output, then render.

Bug report 2 is about a crash when an image is connected to a transform compositor node (and mentions Vulkan backend). The steps are open scene, load image into image node, render. The description is vague but mentions transform node, not the same nodes as report 1.

The key parts: Report 1's issue is specific to Render Layers → Viewer + Group Output non-first input. Report 2 is about transform node and image loading. Different setups, different nodes involved. So they aren't the same issue. Therefore, answer is No.

JSON Data

{
"llm_judgement": false,
"processing_time": 13.389886,
"duplicate_report_number": "155302"
}

### Report flagged as NOT a duplicate by LLM <details> <summary>Vulkan: Crash when image connected to transform compositor node</summary> https://projects.blender.org/blender/blender/issues/155302 **System Information** Operating system:window 10 Graphics card:3060rtx **Blender Version** Broken: 4.5, 5.1 Worked: OpenGL backend **Short Description** while using compositor transform node blender kept crashing dont know the cause i have provided the blend file and the image i dont know if image has any relation to it tho edit: also provided a obs video if blender does not crash on your side **Steps to Reproduce** - Open attached scene - Load provided image inside the image node (should crash here. If not, do next step) - Render image </details> <details> <summary>LLM Reasoning</summary> Got it, let's analyze these two bug reports. First, look at the descriptions and steps. Bug report 1 is about a crash when connecting Render Layers to Viewer AND Group Output's non-first input. The steps involve specific nodes: Render Layers, Viewer, Group Output, with connections to Viewer and a non-first slot in Group Output, then render. Bug report 2 is about a crash when an image is connected to a transform compositor node (and mentions Vulkan backend). The steps are open scene, load image into image node, render. The description is vague but mentions transform node, not the same nodes as report 1. The key parts: Report 1's issue is specific to Render Layers → Viewer + Group Output non-first input. Report 2 is about transform node and image loading. Different setups, different nodes involved. So they aren't the same issue. Therefore, answer is No. </details> <details> <summary>JSON Data</summary> { "llm_judgement": false, "processing_time": 13.389886, "duplicate_report_number": "155302" } </details>

👍 1

Triager-bot commented

2026-04-12 17:11:00 +00:00

Report flagged as NOT a duplicate by LLM

Rendering this Compsite Results in Crash

https://projects.blender.org/blender/blender/issues/151854

System Information
Operating system: Linux-6.8.0-90-generic-x86_64-with-glibc2.39 64 Bits, X11 UI
Graphics card: NVIDIA GeForce RTX 4070 Ti NVIDIA Corporation NVIDIA 580.95.05 Vulkan Backend

Blender Version
Broken: version: 5.0.1, branch: blender-v5.0-release, commit date: 2025-12-15 16:36, hash: a3db93c5b259
Worked: (newest version of Blender that worked as expected)

Short description of error
Attempting to render this composite caused Blender 5.1 to crash. Blender 4.5 rendered without issue.

Exact steps for others to reproduce the error

Open attached file.
Replace the image sources with something from your own system - it shouldn't matter what.
Set a destination for the output file
Render

Here, Blender 5.1 crashes in both CPU and GPU mode. I tested with 4.5 and it rendered without a problem.

LLM Reasoning

Got it, let's analyze these two bug reports. First, look at the description and steps for each.

Bug Report 1: The issue is about crashing when Render Layers image output is connected to both Viewer node and Group Output (but not first Image item). Steps involve creating specific nodes in Compositor, connecting them, then rendering.

Bug Report 2: Title says "Rendering this Composite Results in Crash". The steps are opening an attached file, replacing images, setting output, rendering. But the description mentions it's a composite, but the steps don't specify the node setup like Bug 1 does. Also, Bug 1 has a very specific node connection scenario (Render Layers to Viewer and Group Output non-first slot), while Bug 2 is more general about a composite causing crash, with no details on node connections.

Since the descriptions and steps are different—Bug 1 has a precise node setup, Bug 2 is vague about the composite structure—they don't seem to be the same issue. So the answer is No.

JSON Data

{
"llm_judgement": false,
"processing_time": 15.00255,
"duplicate_report_number": "151854"
}

### Report flagged as NOT a duplicate by LLM <details> <summary>Rendering this Compsite Results in Crash</summary> https://projects.blender.org/blender/blender/issues/151854 **System Information** Operating system: Linux-6.8.0-90-generic-x86_64-with-glibc2.39 64 Bits, X11 UI Graphics card: NVIDIA GeForce RTX 4070 Ti NVIDIA Corporation NVIDIA 580.95.05 Vulkan Backend **Blender Version** Broken: version: 5.0.1, branch: blender-v5.0-release, commit date: 2025-12-15 16:36, hash: `a3db93c5b259` Worked: (newest version of Blender that worked as expected) **Short description of error** Attempting to render this composite caused Blender 5.1 to crash. Blender 4.5 rendered without issue. **Exact steps for others to reproduce the error** 1. Open attached file. 2. Replace the image sources with something from your own system - it shouldn't matter what. 3. Set a destination for the output file 4. Render Here, Blender 5.1 crashes in both CPU and GPU mode. I tested with 4.5 and it rendered without a problem. </details> <details> <summary>LLM Reasoning</summary> Got it, let's analyze these two bug reports. First, look at the description and steps for each. Bug Report 1: The issue is about crashing when Render Layers image output is connected to both Viewer node and Group Output (but not first Image item). Steps involve creating specific nodes in Compositor, connecting them, then rendering. Bug Report 2: Title says "Rendering this Composite Results in Crash". The steps are opening an attached file, replacing images, setting output, rendering. But the description mentions it's a composite, but the steps don't specify the node setup like Bug 1 does. Also, Bug 1 has a very specific node connection scenario (Render Layers to Viewer and Group Output non-first slot), while Bug 2 is more general about a composite causing crash, with no details on node connections. Since the descriptions and steps are different—Bug 1 has a precise node setup, Bug 2 is vague about the composite structure—they don't seem to be the same issue. So the answer is No. </details> <details> <summary>JSON Data</summary> { "llm_judgement": false, "processing_time": 15.00255, "duplicate_report_number": "151854" } </details>

👍 1

Triager-bot commented

2026-04-12 17:11:16 +00:00

Report flagged as NOT a duplicate by LLM

Node editors: Crash when main tree is connected to Group Input node

https://projects.blender.org/blender/blender/issues/137943

System Information
Operating system: Linux-6.13.11-gentoo-dist-x86_64-AMD_Ryzen_9_9950X_16-Core_Processor-with-glibc2.40 64 Bits, WAYLAND UI
Graphics card: NVIDIA GeForce RTX 3080/PCIe/SSE2 NVIDIA Corporation 4.6.0 NVIDIA 570.86.16 Opengl Backend

Blender Version
Broken: version: 4.5.0 Alpha, branch: main, commit date: 2025-04-21 17:28, hash: d791ea7cc2c6
Broken: 4.4
Worked: ?

Short description of error
If a Group Input node is present in the main node tree and is connected to the output (directly or indirectly through other nodes), Blender crashes when rendering.

Exact steps for others to reproduce the error
Render the following node tree in the compositor:

Or the following in the shader editor:

Note: a group input can't be added from the menu, but you can add it by copying it from a node group.

LLM Reasoning

Got it, let's analyze these two bug reports. First, look at the descriptions and steps to reproduce.

Bug Report 1 is about crashing when Render Layers' image output is connected to both a Viewer node and a Group Output (but not the first Image item). The steps involve connecting Render Layers to Viewer and then to a non-first slot in Group Output, then rendering.

Bug Report 2 is about crashing when the main tree's Group Input node is connected to an output (directly or indirectly), in compositor or shader editor. Steps mention connecting Group Input to output nodes.

The key here is the nature of the issue: Bug 1 is specific to Render Layers + Viewer + Group Output (non-first slot) causing crash on render. Bug 2 is about Group Input connected to output (any, maybe) causing crash. These are different scenarios—one involves Render Layers and Viewer with Group Output slots, the other involves Group Input in main tree. So they're not the same issue. Therefore, the answer is No.

JSON Data

{
"llm_judgement": false,
"processing_time": 15.167365000000002,
"duplicate_report_number": "137943"
}

### Report flagged as NOT a duplicate by LLM <details> <summary>Node editors: Crash when main tree is connected to Group Input node</summary> https://projects.blender.org/blender/blender/issues/137943 **System Information** Operating system: Linux-6.13.11-gentoo-dist-x86_64-AMD_Ryzen_9_9950X_16-Core_Processor-with-glibc2.40 64 Bits, WAYLAND UI Graphics card: NVIDIA GeForce RTX 3080/PCIe/SSE2 NVIDIA Corporation 4.6.0 NVIDIA 570.86.16 Opengl Backend **Blender Version** Broken: version: 4.5.0 Alpha, branch: main, commit date: 2025-04-21 17:28, hash: `d791ea7cc2c6` Broken: 4.4 Worked: ? **Short description of error** If a Group Input node is present in the main node tree and is connected to the output (directly or indirectly through other nodes), Blender crashes when rendering. **Exact steps for others to reproduce the error** Render the following node tree in the compositor: <img width="300" alt="image.png" src="attachments/2722bdcf-8f89-44a3-b29a-f10f7bcb245e"> Or the following in the shader editor: <img width="300" alt="image.png" src="attachments/36ee91f0-accb-45e5-b5be-e413f173d81b"> Note: a group input can't be added from the menu, but you can add it by copying it from a node group. </details> <details> <summary>LLM Reasoning</summary> Got it, let's analyze these two bug reports. First, look at the descriptions and steps to reproduce. Bug Report 1 is about crashing when Render Layers' image output is connected to both a Viewer node and a Group Output (but not the first Image item). The steps involve connecting Render Layers to Viewer and then to a non-first slot in Group Output, then rendering. Bug Report 2 is about crashing when the main tree's Group Input node is connected to an output (directly or indirectly), in compositor or shader editor. Steps mention connecting Group Input to output nodes. The key here is the nature of the issue: Bug 1 is specific to Render Layers + Viewer + Group Output (non-first slot) causing crash on render. Bug 2 is about Group Input connected to output (any, maybe) causing crash. These are different scenarios—one involves Render Layers and Viewer with Group Output slots, the other involves Group Input in main tree. So they're not the same issue. Therefore, the answer is No. </details> <details> <summary>JSON Data</summary> { "llm_judgement": false, "processing_time": 15.167365000000002, "duplicate_report_number": "137943" } </details>

👍 1

Triager-bot commented

2026-04-12 17:11:30 +00:00

Report flagged as NOT a duplicate by LLM

Frequent crashing during compositing - Blender 5.1

https://projects.blender.org/blender/blender/issues/156334

System Information
Operating system: Windows-11-10.0.26200-SP0 64 Bits
Graphics card: NVIDIA GeForce RTX 5070 NVIDIA Corporation NVIDIA 595.97 Vulkan Backend

Blender Version
Broken: version: 5.1.0, branch: blender-v5.1-release, commit date: 2026-03-16 18:50, hash: adfe2921d5f3
Worked: 5.0

Short description of error
After downloading v5.1, rendering often crashes during compisiting phase. Blender also sometimes crashes when opedning compsitor while render is ongoing.
I am attaching latest crash log.

Exact steps for others to reproduce the error

Open prism.blend or Crashing compositor - simplified.blend
Render the scne with Render -> Render Image
1 out of 5 renders, Blender will crash
Open compositor editor while rendering to increase the chance of a crash

LLM Reasoning

Got it, let's analyze these two bug reports. First, look at the description and steps for each.

Bug report 1 is very specific: crashing when Render Layers' image output is connected to both Viewer node and Group Output (but not first Image item). The steps are detailed with nodes in compositor, connecting to 2nd+ slot of Group Output.

Bug report 2 is more general: frequent crashes during compositing, sometimes when opening compositor while rendering. Steps involve using provided blend files and rendering, no specific node connections mentioned like in bug 1.

The key difference is the cause: bug 1 has a precise setup (specific nodes and connections), bug 2 is vague about the setup, just mentions crashes during compositing. So they don't describe the same issue. Therefore, answer is No.

JSON Data

{
"llm_judgement": false,
"processing_time": 13.071857,
"duplicate_report_number": "156334"
}

### Report flagged as NOT a duplicate by LLM <details> <summary>Frequent crashing during compositing - Blender 5.1</summary> https://projects.blender.org/blender/blender/issues/156334 **System Information** Operating system: Windows-11-10.0.26200-SP0 64 Bits Graphics card: NVIDIA GeForce RTX 5070 NVIDIA Corporation NVIDIA 595.97 Vulkan Backend **Blender Version** Broken: version: 5.1.0, branch: blender-v5.1-release, commit date: 2026-03-16 18:50, hash: `adfe2921d5f3` Worked: 5.0 **Short description of error** After downloading v5.1, rendering often crashes during compisiting phase. Blender also sometimes crashes when opedning compsitor while render is ongoing. I am attaching latest crash log. **Exact steps for others to reproduce the error** - Open [prism.blend](/attachments/adbc061c-bff7-48dc-961a-b15277d1d3e5) or [Crashing compositor - simplified.blend](/attachments/c6742ac5-a2b7-4402-8d92-d7b15e049246) - Render the scne with `Render -> Render Image` - 1 out of 5 renders, Blender will crash - Open compositor editor while rendering to increase the chance of a crash </details> <details> <summary>LLM Reasoning</summary> Got it, let's analyze these two bug reports. First, look at the description and steps for each. Bug report 1 is very specific: crashing when Render Layers' image output is connected to both Viewer node and Group Output (but not first Image item). The steps are detailed with nodes in compositor, connecting to 2nd+ slot of Group Output. Bug report 2 is more general: frequent crashes during compositing, sometimes when opening compositor while rendering. Steps involve using provided blend files and rendering, no specific node connections mentioned like in bug 1. The key difference is the cause: bug 1 has a precise setup (specific nodes and connections), bug 2 is vague about the setup, just mentions crashes during compositing. So they don't describe the same issue. Therefore, answer is No. </details> <details> <summary>JSON Data</summary> { "llm_judgement": false, "processing_time": 13.071857, "duplicate_report_number": "156334" } </details>

👍 1

Triager-bot commented

2026-04-12 17:11:45 +00:00

Report flagged as NOT a duplicate by LLM

Tabbing into Compositor NodeGroup is Crashing Blender 5.0 Alpha

https://projects.blender.org/blender/blender/issues/143892

System Information
Operating system: Windows-11-10.0.26100-SP0 64 Bits
Graphics card: NVIDIA GeForce RTX 2070 NVIDIA Corporation NVIDIA 560.94 Vulkan Backend

Blender Version
Broken: version: 5.0.0 Alpha, branch: main, commit date: 2025-08-02 20:28, hash: 77563587cd33
Worked: 4.5.0

Short description of error
Crash when entering node group during biewport compositing
I've tried to copy the compositor setup of this video: The Secret to Rendering Vibrant... at 9:31 and 9:51 (Poorly, but that's beside the point).

Exact steps for others to reproduce the error

Open attached file
Switch to viewport render (make sure viewport compositing is enabled)
Tab to enter selected node group

From author:
After turning on rendered mode and activating viewport compositing, I tabbed into the node group I created which led to Blender crashing.
Weirdly even connecting just a value node to the group output will result in Blender crashing as long as the node group is not muted and in the image chain.

Thanks in advance :)

LLM Reasoning

Got it, let's analyze these two bug reports. First, look at the descriptions and steps.

Bug report 1 is about a crash when connecting Render Layers to Viewer AND Group Output (but not first slot). The steps involve setting up those nodes in Compositor, connecting specific outputs, then rendering.

Bug report 2 is about crashing when tabbing into a NodeGroup during viewport compositing, even with simple connections like value node to group output. The steps are opening a file, enabling viewport compositing, tabbing into the node group.

The issues seem different: one is about render time crash with specific node connections (Render Layers + Viewer + Group Output non-first slot), the other is about crashing when entering a node group during viewport compositing. The contexts (render vs viewport compositing) and triggers (node connections vs tabbing into group) are distinct. So they're not the same issue.

JSON Data

{
"llm_judgement": false,
"processing_time": 13.999565,
"duplicate_report_number": "143892"
}

### Report flagged as NOT a duplicate by LLM <details> <summary>Tabbing into Compositor NodeGroup is Crashing Blender 5.0 Alpha</summary> https://projects.blender.org/blender/blender/issues/143892 **System Information** Operating system: Windows-11-10.0.26100-SP0 64 Bits Graphics card: NVIDIA GeForce RTX 2070 NVIDIA Corporation NVIDIA 560.94 Vulkan Backend **Blender Version** Broken: version: 5.0.0 Alpha, branch: main, commit date: 2025-08-02 20:28, hash: `77563587cd33` Worked: 4.5.0 **Short description of error** Crash when entering node group during biewport compositing I've tried to copy the compositor setup of this video: [The Secret to Rendering Vibrant...](https://www.youtube.com/watch?v=hS7uaTquwWc&t=633s) at 9:31 and 9:51 (Poorly, but that's beside the point). **Exact steps for others to reproduce the error** - Open attached file - Switch to viewport render (make sure viewport compositing is enabled) - `Tab` to enter selected node group From author: After turning on rendered mode and activating viewport compositing, I tabbed into the node group I created which led to Blender crashing. Weirdly even connecting just a value node to the group output will result in Blender crashing as long as the node group is not muted and in the image chain. Thanks in advance :) </details> <details> <summary>LLM Reasoning</summary> Got it, let's analyze these two bug reports. First, look at the descriptions and steps. Bug report 1 is about a crash when connecting Render Layers to Viewer AND Group Output (but not first slot). The steps involve setting up those nodes in Compositor, connecting specific outputs, then rendering. Bug report 2 is about crashing when tabbing into a NodeGroup during viewport compositing, even with simple connections like value node to group output. The steps are opening a file, enabling viewport compositing, tabbing into the node group. The issues seem different: one is about render time crash with specific node connections (Render Layers + Viewer + Group Output non-first slot), the other is about crashing when entering a node group during viewport compositing. The contexts (render vs viewport compositing) and triggers (node connections vs tabbing into group) are distinct. So they're not the same issue. </details> <details> <summary>JSON Data</summary> { "llm_judgement": false, "processing_time": 13.999565, "duplicate_report_number": "143892" } </details>

👍 1

Triager-bot added

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labels 2026-04-12 17:12:42 +00:00

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