EKKO DASH BUGGED (?) PLS reply Riot

For some reason it doesn't seem to work to interrupt his Dashes with knockbacks/other form of CC. Janna can't interrupt his dashes for whatever reason I do not know. Is this intended? He still deals dmg and it drives me insane. How am I supposed to peel him away if I cant do anything except using exhaust + shield + heal? T___T