[Gameplay] Katarina walks without Inputs.

I have seen this issue twice today, once myself playing and an enemy playing her. In my scenario, after going into a teamfight and sitting in my ultimate, I ignited a nearby target. After approximately one second of being in my ult, I was silenced and without inputting any move commands, Katarina began to walk toward the direction of where I had ignited my target. I'm sure the case was similar to the enemy Kat.. She was in her ult, got silenced, and began walking in a direction, ultimately to her death.