Complete system shutdown/restart when selecting another photo during AI Denoise

Title: Lightroom Classic 15.5.1 causes complete system shutdown/restart when selecting another photo during AI Denoise

Description of Issue

Lightroom Classic 15.5.1 causes my Windows PC to suddenly shut down/restart when I select another photograph while AI Denoise is processing an image.

The problem is highly reproducible.

AI Denoise itself works correctly. I can process several RAW files consecutively and I have successfully completed a batch of four photographs.

However, while Denoise is still processing, if I click another photograph in the filmstrip to select it, the computer suddenly shuts down/restarts.

Simply hovering the mouse pointer over other photographs, which displays their preview in the Navigator, does NOT cause the problem. The shutdown occurs when another photograph is actually selected during Denoise processing.

System

• Lightroom Classic: 15.5.1

• Operating system: Windows 10 64-bit

• CPU: Intel Core i7-6700K

• GPU: AMD Radeon RX 5600 XT 6 GB

• AMD Software: Adrenalin Edition 26.8.1 WHQL Recommended

Steps to reproduce

1. Open a RAW photograph in Lightroom Classic.

2. Start AI Denoise.

3. Leave Denoise processing in the background.

4. While processing is still active, click another photograph in the filmstrip.

5. The computer suddenly shuts down/restarts.

If I only hover the mouse pointer over another photograph without selecting it, Lightroom continues processing normally.

If I do not select another photograph and simply allow Denoise to finish, processing can complete successfully. I have successfully processed four photographs without a shutdown when I did not change the selected photograph during processing.

Expected Result

Lightroom should continue AI Denoise processing in the background while allowing another photograph to be selected and viewed.

Actual Result

Selecting another photograph while AI Denoise is processing causes a complete system shutdown/restart without a normal Lightroom error message or BSOD.

Troubleshooting already performed

• Lightroom Classic 15.5.1 completely uninstalled and reinstalled.

• Lightroom Classic preferences reset using the Alt+Shift startup procedure.

• Lightroom GPU/display acceleration settings tested.

• AMD graphics driver and AMD Software reinstalled.

• Previous AMD Software/driver incompatibility was corrected.

• Current AMD Software and driver are correctly aligned on Adrenalin 26.8.1 WHQL.

• The problem remains reproducible.

• Opening RAW files directly in Adobe Camera Raw and running AI Denoise works correctly. I have successfully processed multiple RAW files in Camera Raw without a system shutdown.

• Lightroom Classic can also complete multiple Denoise operations as long as I do not select another photograph while processing is active.

This appears to be specifically triggered by Lightroom Classic changing the selected image while GPU-intensive AI Denoise processing is running.