After not having any crashes for the last few play sessions, the game crashed today when performing a regular save. Guess I can get the crashes for all kinds of saves, too.
Furthermore, I'm getting the impression that the bug is related to how long you play. The last couple of session, that where all crash-free, only took about 2 hours each, while I played for about 4 hours today, with the save crash occuring at the very end.
Also, after changing texture memory size, I tried to reproduce the bug by just walking around and pressing F5 every few seconds, but I neither got a crash with lowered, nor with very high texture memory size, in about 30 tries each.
How does it work for other people, who get the crashes at a higher frequency? Do you often get your first crash after a few minutes, or does it take some time?