had the same issue on single player world on PC win 10 where I would break the nether rack that was on fire not putting out the flames, and I would get burned walking over the block where it was.
This is normal, it always wipes worlds when coming from Beta, it suggested to save back up of your worlds before going into beta.
we had this issue I had to uninstall and reinstall MC cause it wasn't updating automatically. We also had the same issue with the realm not updating right away as well and having to load it multiple times. But its basically saying something not up to date on the 1.16.1 version.
I also have this issue happen when ever I leave the render distance and return. I found open them when not loaded cause the crash if items were in them.