Celestial Schism works properly, description of the item says that all Cultivation quests have to be completed in order to perform cultivation change (same description is on the fairy from Boutique).
Players that are unable to use the item are those who got their third fairy from the Boutique and didn't do the Cultivation quests. In this case please just do these quests and you will be able to perform the schism.
I stated already that it's not possible to remove the cultivation quests requirement from the schism mold, so it has to work in the way it works now.