Rek'Sai-Kalista Glitch (NEEDS ADDRESSED)

Ok so I'm going to get right into this. Yesterday a friend and I were playing a custom game against some bots as a stress reliever. I played Rek'Sai and he played Kalista. We found out that if you bind Rek'Sai to Kalista, there's an unfortunate side effect. As Rek'Sai, if you ult past Kalista and she casts her ult at the right moment, it immediately resets Rek'Sai's ult cooldown, and you can immediately use it again. Now this was yesterday when Kalista was bugging out, but it's possible it still works. Just throwing this out there so it gets found now and not after its been abused.