Nezahal, Primal Tide doesn't cast with Omniscience [Investigating]

Nalthazar

Nezahal, Primal Tide reads that it can't have its mana drained or raised, but it does not specify that its mana cost cannot be lowered. When Omniscience is out, Nezahal, Primal Tide does not cost 0 mana. I think this might have something to do with Omniscience draining the mana from all cards in your hand as part of the process of making the cards become 0 mana while it is out. Either way, please try and fix this.

//Edited Title -Brigby