I encountered a crash to desktop with no error message when leaving the cave. Apparently something triggers "save and quit" because if I start the game the character is where I would have expected him to be if the game didn't quit. This means it's really annoying, but not as game breaking as I thought it was prior to discovering that it actually saves the game.
It seems to be related to the time of the day since it works fine during the day and crashes fairly frequently at night. In fact occasionally it also crashes when entering the cave at night.
No mods and no DLC enabled (though all DLCs are installed).
I attached config and log files, though I have no idea how to find the savegame.
Apparently other people have this problem too because there is a thread about it on steam.
Enter and exit the cave at night. This will often cause a quit/crash, but it's not 100% consistent.