LoL: Ranked Moments #17 Kalista Rend Bug LOL

Hello everyone, while playing a ranked game I encountered this rather interesting bug. Seen in the Video above.

So basically what it does as far as I know is...:

1. If you execute an unit with your [E] Rend it doesnt reset instead it goes on cooldown
2. Your next auto-attack after using [E] Rend automatically refreshes the cooldown and also rends the target you auto-attacked

I have absolutely no Idea what caused this but... This is how it started:

and also it fixed itself when I died, so there is that