Teufelix

Hello fellas, i got myself a Magickarp for the Event-Move "Happy Hour". Right now, it's LVL 93 and 50% EV trained and hidden ability but the Tutor says: "Magickarp can't lern Happy Hour". I caught 2 random Magickarp after that but they can learn it. Is this a Bug or because of the ability? On "Smogon" its writen it can learn it even with hidden ability so i can't see why mine shouldn't learn it. -Thanks in advance