Swain passive not working bug

I just played a game as Swain using the Northern Front skin, right after having played a game as Swain with the Tyrant skin and about 3 minutes (2nd or 3rd wave) into the 2nd game with the Northern Front skin i noticed my passive was not going off when i last hit. I all chatted the ez mid i was facing and he noted it too after i said "look my passive isn't going off when i last hit with auto attacks or spells, you know the blue bubble around me" Both my team and their team picked up on it aw all agreed it was not working at all and that it was pretty much turned off. I had no passive the whole game. And yes all the instances where the passive procs were not working, kill or assist didn't give me the chunk of max mana as well as the unit kills. It was jkust a normal and i still won but i was low on mana and below half all game, i found myself having to play very safe and going back often. Not having a passive like that made me appreciate blue buffs a lot. XD Anyway i would really like this to be looked into and i will play another game with Tyrant and Classic to see if this happens again.