When an animal ends sleeping he wakes up and then suffocates inside a block but they get to pass trough the fences

Version of Minecraft, version of Animania, Single Player or Server

Single Person Minecraft 1.12.2
Latest version? Downloaded mod some days ago

Screenshots

https://imgur.com/a/vyJvkho

I'm seeing something similar, where I'll be walking around in another part of the chunk and suddenly see " suffocated in a wall". I can't confirm it's due to them sleeping, but there's definitely something strange going on here.

Can you show any proof of suffocation? The hitbox doesn't/shouldn't change when they are sleeping

I stopped playing Minecraft time ago and deleted that world but I think that it happend when they where sleeping and you move them into a block and when they wake-up they suffocate.