Disappearing mobs

Mobs disappearing/escaping (BUG
My horse tied in a fence disappeared, my sheeps was all over the place after I go back up to the surface (In my world, I live down in a ravine, so I'm always at the bottom). Everytime, whenever I had a cat, dogs, horse, or a cage zombie villager, they disappearing from their position when I come back to them. i hope this got fix.