Realms stopped doing backups and rolled back to 20hours ago

Yesterday we were playing and everything was fine. We made a lot of progress in our game and when we logged in this morning, we were back to 20 Hours ago in our game. When I looked the backups, it had stopped doing backup for 20 Hours but now it's ok, it seems to be doing new backups, but there is a 20 Hours missing in our backups. We lost it !