Well seems the "Farming Skills 14/14" is also broken, though I can't seem to figure out why. I have made the composter and filled it multiple times. It changes to the "Composter_Filling" block but the quest just won't update.
I have gone through the code, and unless I just don't see it, the code looks correct, almost identical to the "Basic Survival 7" quest in vanilla. It just won't read the update.