Kalista and Sion Ult causing some confusion...

My friend and I found a bug, intentional or not, where a Kalista binds to a Sion. Sion ults creating him unstoppable. Running which ever way for how ever long. The thing is when he ults past a Kalista and Kalista uses ult as soon as Sion's ult is FINNISHED he flys across the map landing within Kalista. While this is hilarious and fun I would like it patched.