Syndra W bug

I ran into a W bug in my last game; if you cast W on a target just barely out of range, will take sort of a half step towards it and then just stop without casting W. It happened about 4 times that game, and cost me 2 deaths and a missed kill opportunity. Also, before someone says something along the lines of "the orb must have timed out" or "the minion/monster must have died" I'll point out that I am NOT considering such instances as part of this; although coming to a dead stop right as you reach max range on an orb or minion because it just died/timed out is annoying, I don't feel that's a bug. I DO feel it's a bug, however, when the half HP minion/just QE'd orb makes her come to a dead stop in the middle of a fight without casting W when it comes in range.