steam-runtime-launch-client Error After UMU Update

[Zeabyte]

A couple of days ago, everything worked perfectly. Then in the bottom left corner I saw that some part of UMU was updated. After that no game of mine will launch with any version of Proton any more.

The log:

steam-runtime-launch-client[169]: E: Unable to convert /app fd 16 into path: different file inside and outside sandbox
Monitored process exited.
Initial process has exited (return code: 32000)
All processes have quit
Exit with return code 32000

I have no idea what this error means.

It is not reproducible with native Lutris.

Steps to reproduce

1. Select any version of Proton as a runner
2. Start the game

Expected behavior The game launches successfully.

Actual behavior The game crashes pre-launch after about one second.

Flatpak info flatpak --version: Flatpak 1.15.10 flatpak --gl-drivers:

nvidia-560-35-03
default
host

[ygaeon]

First attempt to launch newly installed CBP2077

$ flatpak --version
Flatpak 1.14.8
$ flatpak --gl-drivers
default
host

Started initial process 62 from gamemoderun $HOME/.var/app/net.lutris.Lutris/data/lutris/runtime/umu/umu_run.py $HOME/.local/share/lutris_games/gog/cyberpunk-2077/drive_c/GOG Games/Cyberpunk 2077/REDprelauncher.exe
Start monitoring process.
Waiting for game to start (first non-excluded process started)
gamemodeauto: 
Setting up Unified Launcher for Windows Games on Linux...
Downloading latest steamrt sniper, please wait...
SteamLinuxRuntime_sniper.tar.xz: SHA256 is OK
Verifying integrity of sniper_platform_0.20241008.104210...
gamemodeauto: 
gamemodeauto: 
sniper_platform_0.20241008.104210: mtree is OK
gamemodeauto: 
gamemodeauto: 
pressure-vessel-wrap[72]: W: /dev/shm not shared between app instances (flatpak#4214). The Steam Overlay will not work.
steam-runtime-launch-client[72]: E: Unable to convert /app fd 15 into path: different file inside and outside sandbox
gamemodeauto: 
Initial process has exited (return code: 32000)
All processes have quit
Exit with return code 32000
2024-10-18 16:29:46,471: Game still running (state: running)
2024-10-18 16:29:46,472: Stopping Cyberpunk 2077 (wine)