Zed - Ult,W+Q = No Dmg?

I was playing zed the other day and I think I stumbled upon a bug with him. I had a normal early game, but when I got my ult... things stopped working smoothly. Whenever I engaged on someone; Ult,W<Q. My Q's were doing no damage, negating ALOT of damage seeing as thats about 70% (give or take) of your damage. Has anyone else encountered something like this...?