[GAMEPLAY] Lee Sin Q Bug

Even though this is Urf it shouldn't affect the outcome. The second part of my Q was cast and I traveled to my target, only that my target (Garen) flashed away and I did not follow his flash. This is completely right if the second part of my Q was finished before he flashed, if not for the fact that he still has my Q marker over his head indicating that the second part of Q was never cast. Furthermore he completely dodged my damage. Thoughts? It almost looks like Draven stops my path (though he's not using his E).