My nether and End dimensions got reset. I teleported to the nether and the portal was missing. It was in the same exact location as before but no portal and no base or tunnels. I know it's the exact location because of the fortress that we first encountered is in the same location.

When I went to the end it was partially reset. The spawning platform was missing the bridge and walls around it to prevent falling off. The actual portal in the middle to return home is missing half of its structure (missing bedrock and portal). Some of the terrain was still jacked up from a few wither battles that took place. We are also missing the original portal that can take you out to the islands but the second one was there from beating the dragon again. 

I did experience a few crashes where my xbox series x just shut off. I reported this crash. I don't know if that is related. I also noticed a couple villagers and animals (foxes, horses, donkeys) were missing.