Intended mechanics of Cass, or bug that needs fixing?

I wanna learn this champion at a high level, and my friend came across this very high level "mechanical outplay", that seems like a bug to me. Basically what happens is that Cass changes the direction where she is "Facing" to ult to get the stun off on people not directly looking at her. This is done by using some really strange interactions with her flash. If this is intended, I'll practice this, but if it's a bug, I don't wanna bother trying to do it. Here is a link to a video on twitch that high lights this, hopefully someone can tell me soon, cause compete league is right around the corner. Kind of reminds me a little bit of a Lee sin ult into flash animation cancel in front of them to instantly kick the opposite way, except WAY more buggy and strange.

(Link to video - https://clips.twitch.tv/rush/FairSheepPunchTrees)