[Gameplay] Lee Sin being able to attack after q when he got hit by a stun

So I was playing Ashe and a Lee Sin landed his first q on me, he reactivated it and I ulted him as he was flying towards me, and even though he was stunned he still hit me with a basic attack. There was a small delay between Lee Sin finishing his dash and the basic attack so it is possible the Ashe ult just run its course as point blank Ashe ult often feels really quick but it is something that should be looked into.