Warwick Q bug

Pretty simple. After using his ultimate, I was unable to use my Q on a target. I use smartcast and the spell just wouldn't go off. Tested on multiple occasions and seemed to only happen against an enemy caitlyn. No snare, no slow was used. To be more specific, I would spam the spell with my cursor over her and it wouldn't go off until about 4-5 seconds AFTER my suppression ended. (As opposed to being able to cast it immediately after it ends.)