Tristana able to leap while stunned. [GAMEPLAY]

While playing ARAM today, we had Udyr on our team and a Tristana on the enemy team. On Udyr's Bear Stance, there is a persistent effect of basic attacks cause a 1 second stun and has a cooldown of a few seconds. I was noticing on that first hit and stun, Tristana was still able to use Rocket Jump, even with the stun indicator (purple circles above head) visible.

It happened every time that persistent effect was not on cooldown. It was very frustrating as we couldn't kill Tristana because she would just Rocket Jump away, then we'd get smashed with the rest of the enemy team's CC then Tristana would walk back to the fight and blast all of us.

Please investigate this.

Thanks