Starting 4/10 my realm reached a size where when the automatic backup is run the IOS client encounters some error condition (e.g. a timeout) which causes it to be disconnected.  The observable effects is that breaking blocks occurs instantly and there are no particles or dropped items.  A few seconds later the IOS client shows a “disconnected from realm” error screen.

When attempting to reconnect the Realm reports a logged in user count that includes my account.  Attempts to reconnect fail without loading resources generating terrain.  Attempts to connect continue to fail for >10 minutes.

However, killing and reopening the IOS client allows me to log back in immediately without waiting the many minutes for accounts to be logged off.

The schedule for backups is not configurable so this error state happens every few minutes.