First off... I have never opted-in on any beta program for Minecraft on Xbox One.

A few days ago Minecraft updated from v1.2.13 to v1.2.14.3 (beta) via auto update on Xbox One.

Today I got a message in-game notifying me about the error to push a beta to non-beta users. I followed the the instructions there to revert from v1.2.14.3 (beta) to v1.2.13 again by deleting the game and reinstall. All my savegames was synced to the cloud.

After installing / rollback to v1.2.13 and loaded my maps they are now corrupted with bunch of missing blocks (huge areas). Pretty much all areas i have built anything. My maps in the cloud is corrupted too.

This is a major error / bug.

Multiple reports from users here:
https://www.minecraftforum.net/forums/support/xbox-one-support

There is also tons of similar comments under the informational post about this from in the Minecraft Game Hub on Xbox One.

And finally... How do I recover my worlds that I have poured 100+ of hours into with my friends? Microsoft told me that you control the cloud storage and can revert to earlier versions. In my case 1.april is before the update.

Update: After installing the aquatic update (v1.4) this issue is resolved for me.