Shove voles (and dreckos) sometimes get locked up permanently trying to climb up.
There are some common elements of this lockup:
- The critter is always trying to climb up
- The critter drops down after climbing a single tile. The drop sound can be heard
- The critter will not stop trying to climb until something forces them to perform a different action. Usually it means meteor in the face, but I think I saw one critter unlock itself to eat food.
- (Not sure) Seems to happen more often on surface. I don't recall it happening to dreckos locked up in those small hydrogen/chlorine pockets. Related to meteors changing terrain?
I wanted to attach save, but the save got a different bug: the vole you see on screenshot got buried under regolith on save+load. This may be related to this bug.
Not sure, but it often happens by itself when there are voles on the surface.