1.0 Tidy Estates (clear 55 grass) seems to be broken

At least the stat stat_grass_cleared_count is not used in the lua files, should be increased in my opinion in clearable.go in method Harvest, shouldn't it ?

When planting grass of 70 cells and clearing it the achievement was not awarded

 

Does it only apply to grass during the singing event?

 

No, singing grass uses another session variable IMHO