Yasuo bug?

While I was playing ranked there was a Yasuo on the enemy team and I was Caitlyn. At one point in the game I used my trap and trapped Yasuo but Yasuo knocked me up and ulted me before the duration of the trap was over. This was either a bug or this yasuo was using some kind of hack. I am not jumping to any conclusions but I would like this to be looked into more. He had no cc reduction or anything like that. If there is a explanation for this then please tell me. His summoner name is Shadowmere 17.