Possible Syndra Bug?

I was playing Syndra on pbe against the new bots and stumbled upon a possible bug with her eq combo. Sorry I don't have video evidence, but I managed to consistently create the bug on both pbe and live servers (i used snowday syndra each time). After using Scatter the Weak, if you use your Dark Sphere right at the tip of your E's range you cause the game to lag a little bit before pushing the orb forward instead of the traditional Q+E. The stun still works but it seems to be faster. I don't know if this is an actual bug and I'm just stupid, but I haven't seen that specific combo work all the times I've played