Valve has launched another small update for the Steam Deck with SteamOS 3.6.6 Preview now available for testing which may be essential if you're playing ELDEN RING.
Fixed a an issue with a rare session crash during early startup of ELDEN RING
Fixed a general issue affecting all units on 3.6, and OLED units on 3.5, causing a slow memory leak during gameplay
Fixed a DSP firmware crash with previous 3.6 versions that could result in internal sound disappearing until next reboot
Improved responsiveness of session restart in case of session crashes caused by certain GPU errors
Fixed an issue that could cause videos to stutter in titles such as BlazBlue Centralfiction
Some pretty good fixes. Unfortunately you'll need to be on the beta/preview channel to get them, but hopefully it won't be long before they come to stable.
Elden Ring just updated a day ago for the DLC, and it introduced multiple issues. If you haven't played a lot of sessions in the past day you probably wouldn't have noticed the issue.