Bug with Cassiopeia and Taliyah

I was playing Cassi, and was against a Tali. She Q'd me and as she is on her 2nd or 3rd shot of her Q I ult her. Well it did not stun, but rather just slow her because she was walking backwards. However as I am sure you all know, when Tali Q's she is stuck facing a certain direction. So therefore my ult should have stunned her instead of slowing her. I know it was because she was walking backwards that it didn't but she was still facing me regardless. Personally I think this is a bug that should be fixed because her ult even states, "Cassiopeia releases a swirl of magical energy from her eyes, stunning any enemies in front of her that are facing her and slowing any others with their back turned." Unless it is because she kind of twirls whilst using Q, and if that is the case, that is near impossible to land on her lol. I look forwards to hearing back about it though. Thank you for your time, and I hope to see a bugfix note about this in a future patch.

Zaph Treybourne