1.17 (Bedrock), 1.18 (Bedrock)
Steps to reproduce
Create or join a realm.
Notice that mobs will start to freeze, containers and inventory won't open
Make sure everyone leaves, or wait for everyone to just be disconnected.
You resume what you were doing.
The realm resets to what it was when you first joined.
According to this comment, template worlds locked at 1.17.11 do not have this issue when uploaded to a realm. The identical template world without the version lock does have these issues.