Galio Taunt Bug Patch 8.19

So I was just in a ranked game when what i'm pretty sure is a bug happen to me with Galio's taunt and almost lost us the game. Here's what happened.

Key board: I flashed, pressed W and released it immediately. What Galio did: flash, auto attack passive animation, taunt phase 1 and no reactivation..

I'm walking around with my taunt charging with my finger well off the W key already.. I'm sure re-pressing the W key would have activated it, but surely this is not normal as Galios taunt usually without fail, activates on the release of the key.

My theory is that it has something to do with ability queuing, I have a feeling the game accepted my W command at too similar of a time as the auto attack passive animation and decide to AA first then cast W, but in that split second I've already pressed W and my finger has come off the key board. Breaking the way the W is supposed to work.

I have no idea how any of this is coded my theory is no more than a logic guess, all I know is that it was incredibly frustrating to have that happen and get flamed by unknowing teammates.

I have attached a link to the clip if that helps slowing the video down might be necessary as its only a 3 second clip

Anyone else had trouble with this? Is this supposed to happen and i'm just a noob? Some info would be awesome.