Irelia stun doesn't seem to work on Renekton when he uses his dash

Every time renekton is in the middle of his dash and irelia attempts to stun him, he will get hit by the effect (because he gets marked) but does not actually get stunned. This happened several times throughout a match I played. The only time I could successfully stun Renekton was when he was not dashing so I think it is some kind of glitchy interaction between those abilities. Match is linked.