Terrain changing in my Realm

The terrain in my Realm is changing.  Tunnels are appearing,  structures I've built partially vanish, etc. I have verified with the other people on my Realm they have not made these alterations.  In the video provided the area I'm showing was a flat field with trees and no tunnel. I had flattened it and planted the trees myself. The field was intact the day before I took this video. The next day when I logged on this tunnel was there.   In the photo you can see the top of a building just vanished.  It presumably wasn't hit by lightning as as you can see the lightning rod on the roof remains.