[Compat]: proton-cachyos bleeds external mouse movement into the games, causing an inhumanly fast movement

[FernandoMMuniz]

Game name

Return to Castle Wolfenstein, Half-Life 2

Steam AppID

9010, 220

Proton-CachyOS version

proton-cachyos-11.0-20260429

GPU

NVIDIA GeForce GTX 1650

Video driver version

595.71.05

Kernel version

7.0.3-1-cachyos (64-bit)

Full system information report

https://gist.github.com/FernandoMMuniz/b2c0be736f8095472e0d533a8f42c24a

Please confirm the following before submitting

• I haven't found an existing compatibility report for this game.
• I have checked whether there are updates for my system available.
• I have verified the issue is present when using Proton-CachyOS-SLR from this repository.
• I haven't encountered this issue using an official Proton release (Proton, Proton Experimental, or Proton Bleeding Edge).

Symptoms

Half-Life 2 and Return to Castle Wolfenstein have a sudden very fast movement if the pointer/mouse/cursor goes out of the game layer, then goes back from somewhere else.

This behavior does not occur on Valve's Proton 11 (Beta).

Steps to reproduce

While in either game, take a screenshot with Spectacle, save it by clicking on the Floppy Disk icon, then close the Spectacle window that appears by clicking on its X button, which will transfer the focus back into the game's layer.
In Half-Life 2, the camera will drastically move immediately.
In Return to Castle Wolfenstein, the camera will only drastically move if it detects any pointer/mouse/cursor input.

587944138-39e18d43-6e95-42d0-8782-91c3a147aa09.mp4

587944199-bb5648f3-70a5-4ba1-afa0-300fad39dea3.mp4

Log from Proton-CachyOS-SLR

steam-9010.log

Log from recent Proton Experimental

steam-9010.log

Log from Proton-CachyOS Native (if relevant)

No response

Additional context

Both logs are from Return to Castle Wolfenstein.

[loathingKernel]

Same thing as the other issue, please confirm that it is not happening with not enabling winewayland.

[FernandoMMuniz]

Both issues don't happen on proton-cachyos-11.0-20260429 after removing PROTON_ENABLE_WAYLAND=1 from /etc/environment/ and rebooting my notebook.

steam-9010.log