Kennen Ult bugged [GAMEPLAY]

I was playing ARAM as Kennen and could not use my ult no matter how many times I would try it wouldn't pop. Random side info - Using the Kennen M.D. skin, Rune set up was ELECTROCUTE, CHEAP SHOT, EYEBALL COLLECTION, RAVENOUS HUNTER, TRIUMPH, AND CUT DOWN. Item build - Zhonya's Hourglass, Sorcerer's shoes, Blasting Wand, Amplifying Tome, and Ruby Crystal. First time having to report a bug I hope that info helps and i hope it was an isolated case.