Grass is spawning under water in the Jalsphire Plains and in Liroth, causing cascades of chunk updates when the dimensions get loaded:

Vines are spawning floating in mid air in Damnation:

Thank you for your patience and your report! They are greatly appreciated!

Screenshots one and two were caused by incorrect noise settings for the water checks
Screenshot three was caused by the feature having an incorrect block (in this case: air) being an allowed block to be placed on

Both of these are fixed in the dev build and will be pushed out to version 1.19.2 through 1.20.1 soon.

Latest build fixes this issue!