Volibear passive bug.

I was playing a ranked 5 game with some friends as Volibear. At one point I got caught out by Warwick and Draven got ulted by Warwick and died. This was about ~20 minutes in. For the rest of the game (47:29) my passive would not activate. I was watching my health whenever I got low but to no avail.

My build was Chilling Cinderhulk smite, Mobi boots, Righteous Glory, Thornmail, Spirit Visage, Maw, and upgraded stealth totem.