Ahri's W sometimes fails to target enemy

On occasion I've had 's 'W' (Fox Fire) seems to either fail to target an enemy champion, targeting a nearby minion or straight up failing to target anything. The happens with the rear-most Fox Fire after turning 30 degrees. It's a little hard to say with absolute certain that its a targeting issue since Fox Fire targets enemy's in a somewhat unique manner however I still feel comfortable saying something is bugged with it. Like almost no distance before **Spirit Rushing ** outside to her melee range and having only 2 of the 3 target the enemy in an otherwise uninhabited area. Since her melee range is about where her Fox Fire max range is (at cast), inside of that should have not question as to where it targets, but it seems to fail to do so. If i had to guess I'm guessing the issue lies with casting **Fox Fire ** while ulting.