We have an active realm with an average 5 people connected at a time.  World is less then 500MB, and less then 2 weeks old.  We have been having multiple disconnects per day since the aquatic update.  We've logged the times and noticed it happens exactly the same time the realm does the automatic backup.   It also seems to occasionally happen at the exact time someone exits the world, even when exited properly, but this also lines up with a backup.  In a 12 hour period we had 9 logged disconnects each corresponded to the backup times shown in the attachment.