Following the automatic update to version 1.13, I opened my realm only to discover that all builds that were done in the past 3-4 months were completely wiped from the map. The realm have been effectively rolled back to the state that it was when it first spawned. I have attempted recovery of the realm by restoring a backup of the map from a few days back, but all that did was reload the same empty map.

I have searched for possible solutions but this issue does not appear to have been reported by anyone else.