From time to time I have observed, that a "damaged" save (after incorrect RBA collapse, e.g. due to a CTD or #119 ) restores the character not in the place he/she was, but in Overworld, not far away from portal, more specifically - near the cave entrance.
I never paid attention to it, however today I got a PET ERROR: Unfollow pet. Yes, the freeze happened in Desert and the RBA was closed by kill. As the character "revived" in the overworld after the crash, the pet was no more.
OOOps. Update. The pet is still in the Desert. And started following the player character again as soon as touched. So that shouldn't be a serious error after all :) If pet isn't lost, it's no worse than just a simple crash that caused it.
Note: It was the lightbulb-pet (or what's it's name is?) that was unfollowed. And the LIGHT 1 actually still was shining for all the time - even after going through portals a few times.