Compatibility Report

• Name of the game with compatibility issues: Cyberpunk 2077 (Mod Organizer 2)
• Steam AppID of the game: 1091500

System Information

• GPU: AMD Radeon RX 580 2048SP
• Video driver version: Mesa 25.3.5-arch1.1
• Kernel version: Linux 6.18.9-arch1-2
• Proton version: Proton: 1770737294 experimental-10.0-20260210

steam-13855171773709942784.log

I confirm:

• [x] that I haven't found an existing compatibility report for this game.
• [x] that I have checked whether there are updates for my system available.
• [x] It's not a problem with the mods, since the game runs normally when I run them with older versions of Proton.

Symptoms

Mod Organizer 2 won't open the game after installing mods with their respective WINEDLLOVERRIDES, where as it previously opened normally.

Reproduction

Install Cyberpunk in /mnt/ssd/Games/MO2 Cyberpunk 2077.
Set up steam runtime with: Proton Experimental
set the launch configurations: WINEDLLOVERRIDES="winmm=n,b;version=n,b;audioware=n,b;ArchiveXL=n,b;TweakXL=n,b;Codeware=n,b;mod_settings=n,b;input_loader=n,b" %command% (These are the mod DLLs that I had always used until now, when they started failing in new Proton updates.)
Launch via ModOrganizer.exe in steam and then launch the game inside Mod Organizer 2.

Clarifications
It's not a problem with the mods, since the game runs normally when I run them with older versions of Proton. However, when I noticed this started happening, I decided to report it so it doesn't become a recurring issue with Proton. This is my first time reporting a problem, so I hope you understand and can fix it. Thank you.