WW Ult can be stopped by Ez Flash

Had a game the other night where this weird bug happened. I was playing WW and ulted Ez at point blank. He used his kit flash to get away but I hit him. I know I did because WW doesn't just stop mid flight and wave his arm for a brief second. But the second he was out of his flash, the animation of WW's ult stopped and no damage and cc were continued. He didn't have any items or abilities that could cancel the damage and the cc. No one else was near him.

NERF EZ! He has self peel from WW ult!!!

EDIT! I just remembered that this same thing happens when I play Singed and try to flip him. This I can understand happening a bit more. It's just the ult mitigation that bugs me.