It was different in each of the (now 3) times, but the similarity was that I was drawing a screen (relative mode if it matters) and then exited (once just by exiting, another time by opening another quest, the third time I'm not sure).
EDIT: Now the 4th crash today, and this on different quests. I'm pretty sure I can re-create this if needed. I'm getting an access violation at 0x7C910A19.