We are having the same problem, the realm backup was 5h ago, and when everyone disconnects and comes back, its rolls everything back to that point, happened 2 times already.
Its a problem being worked on, realms are not doing their usual backup, literally almost everyone (including me) is having this problem.
Check Realm Reddit and you will see Minecraft Realms on Reddit
We are having the same problem, the realm backup was 5h ago, and when everyone disconnects and comes back, its rolls everything back to that point, happened 2 times already.
Its a problem being worked on, realms are not doing their usual backup, literally almost everyone (including me) is having this problem.
Check Realm Reddit and you will see Minecraft Realms on Reddit