Mobs that shouldn't despawn are DESPAWNING

I experienced that issue multiple times as well, for all kinds of mobs that were not supposed to despawn.

The only solution I found is to keep mobs in a single chunk - as soon as they can move frome one chunk to another, they will eventually despawn.

Thank you for your report!
We're actually already tracking this issue at MCPE-47922, so we will resolve and link this ticket as a duplicate.

If you would like to add a vote and any extra information to the main ticket it would be appreciated.

If you haven't already, you might like to make use of the search feature, to see if the issue has already been mentioned.

Quick Links:
📓 Issue Guidelines – 💬 Mojang Support – 📧 Suggestions – 📖 Minecraft Wiki

I'm currently playing bedrock 1.17.11 on my phone, and this problem is still happening, my cows, chickens and horses/donkeys (with name tags and saddle) despawn over and over again, it's very frustrating 

This is the second time this happened except this time my villagers despawned!!! I’m very fed up. I’ve lost diamonds, iron, leads, and saddles!  At first it took my cats, dogs, named donkeys, horses with saddles and armor on, axolotls that were put in buckets, but now my dogs, horses, cats, donkey, and villagers this time! I spent hours making a villager breeder containment area and just put them in like two days ago and yesterday night they all despawned! And I had just invited some of my friends to play on my server I believe my friends horse with a saddle, diamond armor, and lead just disappeared. I love playing with my friends but they’re getting fed up with the glitches so am I. This has been going on for months why hasn’t it been fixed yet mojang? It’s been two years since this was first reported.