This is a big single player K2 map (10K spm) with quite a few mods installed (including LTN). I don't have anything else that should be affecting the character (i.e. no teleporting mods, god mods, invulnerability, etc.). One exception might be jetpack, but my character was on the ground when this happened.
When I exited the screensaver, control resumed at a random stop (not where my character was when the SS started). I was in something like god mode. I had no character associated with the player (confirmed with LUA). I could move and open interact, but I had no inventory ('E' did nothing). I confirmed that my original character was back where the SS started with all inventory, etc.
Thanks for the pointer on the AFK setting. I'll double check that it is indeed not getting set.