Maokai Bug[GAMEPLAY]

Played a game against a Yasuo top who leveled E first. For the first while, his E wasn't proccing my (Maokai) passive. But started working suddenly for no apparent reason.

-Take Maokai against Yasuo -Level E on Yasuo first -Start spamming it

Maokai's passive will not stack and there is no pattern I've found that allows Yasuo's E to start stacking Mao's passive after a while.

This seems to be consistent if E is leveled first on Yasuo.