Been struggling with this one, was finally able to isolate the origin.

Since the last update players always die of generic no matter where they log off. disabling the plugin fixed this. I only have one zone with the killsleepers flag and it's a very small one, it's impossible that it would affect all players.

Edit: but it does! for some reason the flag is global and not bound to any zone.

you spawn inside this nosleeper zone and the only way out is a teleport (NpcTp) or noclip for admins. removing all killsleepers flags worked and fixed the issue.