Scold's Bridle + Catalysis + New unique charms doesn't work?

Scold's Bridle(Take (25–100)% of Mana Costs you pay for Skills as Physical Damage) + Catalysis(5% of Damage from hits taken as Damage of random element) + New unique charms(trigger on taking fire/cold/lightning damage) doesn't work?

But Fireflower + Ngamahu's Chosen works? Can someone explain why?