In testing my old world in 1.16 snapshots, I noticed with each snapshot, the Nether Wastes Biome would change, e.g. the previous snapshot it changed to Crimson Forest, with the latest snapshot it changed to Basalt Delta.

I'm not sure if this is a bug, or something that will be automatically rectified with the final release, but wanted to raise it to see if anyone else had the same problem.