Since the update to 1.12.0, Realms no longer properly back up your save data.

Normally, it backs up every 20-30 minutes, and you'll see something like...

Realm - 12 Minutes Ago - 342.39mb

Realm - 45 Minutes Ago - 340.45mb

Now, every new backup it makes without fail is 0.00mb. When clicking on any backup, it takes you back to world spawn with a locator map.

This is on the Nintendo Switch but I would not be surprised if it affects other versions. Honestly, this is an enormous oversight and MC/MJ needs to initiate a hotfix ASAFP. Seriously, if it's not fixed in 1-2 days a lot of people are going to lose their worlds/lose the ability to save their worlds/backup their worlds/fix their worlds with griefing. If this effects everyone who owns a Realm, thats a serious issue. Little bugs that affect the game are one thing, but big bugs that affect not just people who pay the game, but people who pay microsoft a monthly fee to rent a serer? Yeah, a modicum of QC here please.