Nether forts spawn less in versions of the Nether Update. I used chunkbase nether fortress finder to make a comparison. Red dots are nether fortress, big red dots are 0 0 coordinates. This bug is ruining a lot of the new stuff! I have a server were we host 1.16 UHCs, and it's literally impossible to get a fortress! Players going to 3k, 4k to get a fortress is to much. You should fix this bug, and if it's not a bug, you should make fortress more common. There's also some example where there are 2 forts, just 2 forts in a 2000x2000 radius.

Seed 105008760 in version 1.7-1.15.2:

Same seed in 1.16-1.16.2

Same seed in a smaller radious, version 1.7-1.15.2:

Same seed in a smaller radious, version 1.16-1.16.2: