Can't smart or mouse cast Q, R, or B on Katarina.

I was playing as Katarina in a custom game to try her out, and lost the ability to smart or mouse cast Q, R, and B mid-round. This happened after I used a combo (including ult) to blow up an enemy champion. I suspect that between Luden's Echo and/or the passive are to blame, but I can't really say. I loaded another round and was back to normal.

Video is evidence of the broken commands, not the actual problem's beginning.