I have a realm newly created a few weeks ago, no cheats, with a walled lighted village. Had up to 5 iron golems all now despawned, tamed horses de spawn frequently, sheep are despawning almost as fast as I breed them, villagers too. New villagers do spawn but have to be levelled up again. Mobs in general despawn quickly especially horses which are now almost extinct anywhere in the world. Oddly I’ve only encountered Pillagers once in many hours of activity. This morning I’m faced with levelling up all the weaponsmiths from scratch again. We access the realm from both iOS and Windows. Happy for Mojang to use my realm form debug.
I have the same problem here on two iPads. Issue seemed to start with in game crashes yesterday, but now won’t get past the loading screen on both.
I started a new ‘test’ world in my realm as the old one had missing mob issues. Everything ok for around a week. So this morning, I noticed a bunch of mobs had disappeared from my realm; sheep, turtles, lamas, even zombies and skeletons seemed in short supply compared to when I saved and quit the previous night - it was noticeable. I checked the backups and my world was smaller this morning than it was last night. Worlds normally grow in size not shrink. This reduction in size supports the theory that something is happening during save/load or while the world is not in use. I’m going to revert to the largest backup and see if it happens again.