[GAMEPLAY] Warwick's W cooldown timer issue

Multiple times in each of my games in which i play WW, after using his W the cooldown timer 'animation' will not start, and the image displayed will be the same as if the ability was off cooldown and ready to use. However, this issue does not occur with each instance of my using his W. Unfortunately I can't say for sure what exactly causes this to happen or give a step-by-step on how to replicate this problem.