Renekton unable to auto attack for short period of time after using W.

From what I can tell it isn't 100% replicatable, but was just in a normal game playing Renekton and every now and then I would use my W to stun an opponent only to find myself sitting completely still for 1-2 seconds after the use of W (application on the enemy, not just pressing W). This would only happen if my input immediately applying the W was another basic attack. If the W was followed by a spell use or item use such as Tiamat or Q/E, things seemed to work fine. I apologize for not having a video of the bug.