[Gameplay] Hurricane still attacking while CC'd

So I was spectating a featured match recently and I saw that the Kalista got CC'd by Cassiopeia's Ultimate but for some reason hurricane continued to attack and shoot bolts even though Kalista was unable to attack. You can see in the gif that the bolts keep shooting out from the orb and that kalista is healing as well from lifesteal.

Not sure about reproduction of the bug.