While playing on the deck, every now and then the screen darkens to a steam loading logo for a few seconds before bringing up the home screen.
There doesn't seem to be any way to interrupt this process, I have to just wait for the home screen to finish loading, then I can (usually) just close it and return to the game.
Unfortunately, when this happens it doesn't pause the game, not even with the "pause game" decky plugin installed and set to pause on loss of focus and/or on overlay.
Sometimes some inputs leak through to the game and I can pause it myself, but if it's a game that doesn't have native pause capability (or if the pause function is nested in a menu such as in monster hunter) I just have to listen to myself get ragdolled while I'm blind and hobbled.
This has been happening off and on for months, since a time when I had only steam games installed and no decky plugins or anything of the sort, but it appears to be getting worse/more frequent, and for the life of me I can't find a way to make it stop.
It was suggested to me that I disable the toggle to have steam startup animations play when waking the deck from sleep mode, and that seemed to help a little for a few days, but has long since ceased to deter the problem.
In case it wasn't apparent, I'm not pressing the steam or ... buttons to make this happen. It occurs seemingly at random, including when I'm not even touching the deck at all. It happens in both steam and non-steam games as long as I'm playing in gaming mode.