Your system information

• Steam client version (build number or date): Steam Deck Stable, April 3, 2025
• Distribution (e.g. Ubuntu): ChimeraOS 48
• Opted into Steam client beta?: No
• Have you checked for system updates?: Yes
• GPU: AMD

Steps for reproducing this issue:

1. Start Steam in Steam Deck mode (e.g. in SteamOS, ChimeraOS, Bazzite, or a similar distro) on a system with multiple audio output devices
2. In the Steam audio settings, change the audio output device
3. Restart the computer
4. Check the Steam audio settings and observe that the audio output device was reset

Using strace, it is observable that Steam is calling the following command:
[pid 321547] execve("/usr/bin/wpctl", ["wpctl", "clear-default", "1"]

This issue was introduced many months ago, but it was not clear what the culprit was.
This is causing a lot of grief for users of SteamOS-like distros.

It has been reported to me by some users (but I have not verified myself) that this also affects SteamOS on the Steam Deck when docked and/or using external audio devices.