[Gameplay] Wither not displaying cooldown animation

I was playing Nasus earlier and noticed that Wither would still be displayed as available for use even after using it on a target. I thought that I must have misclicked and not used the skill, but the initial target would be withered, and I was unable to cast the skill again for its normal cooldown duration. It basically worked as normal, except that I was unable to see when the skill was next ready for use, and would just have to keep spamming it during fights or count in my head. I didn't grab a screenshot during the game, and was unable to reproduce the issue in a bot game during the same session. Everythine else worked as normal.