Draven dropped spinning axe bug.

Not sure if its a bug or not but i've noticed well playing draven if i have a spinning axe queued up and i throw it at a minion but the minoins dies just right as the axe barely leaves my hand not even half way it will drop the axe. i'll lose the spinning axe and to top it off i won't be able to auto attack from that side until i activate another spinning axe again. It will also be visual as well there will be no axe in the hand that the axe was dropped, it will just be an empty hand. I'm pretty sure its a bug, but maybe it was intentional i know it doesn't do it if the axe reach the minion but it dies before you last hit it. it's pretty rare but an annoying bug i've only seen it happen maybe 5 out of my last 20 draven games.