There are Item frames in my vault that tend to disappear and reappear occasionally in my house. I have a fenced off area outside where I keep my Mooshrooms and they have disappeared and reappeared as well. This has only happened twice now. I recently put a saddled horse In my mushroom cage and it disappeared as well. I have not noticed any other items missing and it seems to be affecting only this one chunk. I attempted to break the item frame to see if it would appear but it did not. I can hear the Mooshrooms mooing and when I tried to hit them with a weapon I heard no sound that would indicate that they were damaged. I will attach more Pictures if the items reappear if that's allowed. I'm afraid to quit and save when this happens because, I fear my items will not be saved if I quit. I am unsure of what caused these incidents to occur but, I might've left the chunk both times and caused it to render again. I'm not entirely sure though. Thank you for your time.
EDIT: Saving, quitting and reopening the game seems to have temporarily resolved the issue