Gangplank's Q

So basically I've been experiencing this since the start of preseason. So the thing is, whenever i press Q with gp, targeting a minion, if the minion dies while Q animation plays ( gp pulls his gun towards the enemy ), he doesn't shoot at all but the Q still goes on cooldown. Also, i gave an example with a minion. It can be anything. Jungle camps, low hp champion etc. Whatever gp shoots at, if it dies while his animation goes on, his Q goes on cd regardless if he landed a shot or not