API/Modloader
Fabric

Describe the bug
Grass cannot spread between different overgrown blocks: overgrown stone can't spread grass onto dirt, meadow grass can't spread grass onto dacite, and all other combinations fail as well.
This also affects overgrown netherrack, but, with recent bug fixes, that behaves like nylium now instead of grass. Still, if you'd like, the other grass blocks could spread grass onto netherrack, while overgrown netherrack itself cannot spread without bone meal, as if grass has a hard time growing in the netherrack or somethin'. Or you could have them be separate things.

To Reproduce
Build these grass spreader palette thingies:

Run /gamerule randomTickSpeed 99999 to make the game process grass spreading very quickly. If this was working, every palette would be fully covered in grass (potentially save for the netherrack blocks).

Expected behavior
Grass block, meadow grass block, overgrown stone and overgrown dacite would all be able to spread grass onto dirt, meadow dirt, stone and dacite.