Animals and pets despawning for no reason

I usually would play in my survival world with no problems until I got an update, I joined my game with my friend and it took me a little while after finding a pink sheep that I would put it in our sheep pen. When I get there none of our sheep are there. We worked so hard for them, it may be because they had a huge pen but I don’t think that’s the reason because in the past we’ve had the sheep pen for a couple of weeks there and took two long adventures and when we came back they were still there but all of sudden they despwaned now? Not only this But me and my friend had two horses, they both had horse armor and a saddle. Plus one had a name tag, they despwaned too. Really upsetting. My dogs were despawned too. I start making a new sheep farm today, I walk away for 2 minutes with my friend to go to bed and we come back and the sheep we just received despawned, even on a lead. I kind of found it weird how after the horses and sheep disappearing, that i all of sudden see random horses and sheeps walking around, sounds normal but way more then usual, i even saw two pink sheep. My game is very odd. If this is a bug or some sort of thing I don’t know and i can fix i would really like to know because i am very annoyed i can’t have a sheep farm or horses, without them despawning.