Yasuo ult goes on cooldown without doing anything

Well this weird bug happened to me in my last game, an enemy was knocked up in a fight so i pressed R, the spell went on cooldown, my character drew his sword but nothing happened, the ulti didn't go off but you can clearly see in the bottom left corner that it went on cooldown. Rito plez fix. Also this is the first time this bug has ever happened to me.