Mob Issues

So I have been playing on Minecraft Pocket edition on my phone with one of my friends through out microsoft accounts. I had tamed several dogs, and we had a couple of cows. I left the game by swiping out of the game and not pausing and leaving. I came back and everything was the same except the dogs and cows had disappeared. I realized my issue and retamed dogs and cows and then paused and left. I assumed it would save progress from then on, but when i went in and just swiped out, all the mobs disappeared again. I have played for years and ended almost every time by swiping out but I have never had anything like this happen. Can I get some help?