[GAMEPLAY]Yasuo can not ult on shyvana ult

I have played a game with a friend as shyvana and him as yas. and whenever i ult the enemy team and we attempt to wombo, he says he is smashing his ult and can not get it to go off whenever I ult them. this happened multiple occasions and it's easily repeatable. Have a couple friends play against you and a friend. one of you shyvana the other yas. hit lvl 6, let shyvana ult then watch as yas cant go in. very annoying bug almost cost me a ranked match