frames with items vanishing from the wall

What I expected to happen was...:
I had 32 frames with food items hanging at a wall, where they should have stayed.

What actually happened was...:
When I entered the room one time, all but seven frames were gone. a torch hanging amidst them was still there.

Steps to Reproduce:
After a while of gamepöay, the game had started to lag. Don`t know if it has something to do with it.