Axolotls And Tamed Pets Disapearing?!

I was on a completely fine none laggy world (not realm) on my ipad I had found some axolotls when I was mining so I scooped them and once you have scooped an axolotl up they don’t despawned right? I put my axolotls in a pond I made for them then I logged off for the day and when I logged back on and joined all my axolotls and tamed pets were gone?! (dog cat) the axolotls pond floor ( Made out of sea lanterns) was lit so no hostile mob would be able to kill them so I am just going to keep my axolotls in buckets till this bug is fixed.