[Gameplay] Warwick's abilities don't work after his ulti

When playing Warwick lately I have found that if I use my ulti during a fight, the rest of Warwick's abilities will not activate. Namely i cannot use my Q or W skills after using my R skill. When clicking them nothing happens and it takes several seconds out of battle before they start to work again.

1. Use ulti on enemy champion 2. As soon as ulti is finished try using Q or W abilities

This happens irrespective of whether I'm using the hotkeys or clicking on the ability icon with my mouse. The Q ability doesn't activate regardless of whether it's targeting a champion or a minion/monster.