Bush Vision Bug

Situation: I was fighting a Riven as Kayle. Riven was in a bush that had my sight ward, I had backup and ult so I moved into riven's face. I was just outside the bush and riven was just inside the bush. The instant my sight ward expired, I lost vision of her - even though she was actively using abilities and aaing me - I could still see the animations firing. I ended up winning the fight, but I thought the situation was very strange.

Possible cause: Ward expiration resets the bush's vision block, even when this should be overridden by the reveal caused by attacks.