On my 1.16.3 server if I add version 8.1.0 then all of my biomes are swapped around. They're still in the same place, they just change to the wrong biome. Taking out this mod then reverts them back to normal.

Please provide more information as described in the issue template (the initial value of the text box when you create an issue).

Maybe related to #4842? (Although, yes, more info needed.)

A user reported back that it will be fixed by the linked update. This will be in beta3