So against Jarvan IV, Quinn's E is completely negated when Jarvan IV uses his E+Q Combo. Even though tips and tricks states that it can be disrupted by displacement spells. I mean if you can kick off Shyvana ult why can't you kick off a Flag and Drag?
Not a bug, completely intended. Quinn's Vault [E] counts as a dash. Any dash can be interrupted (Lucian & Graves E for example). This is why Jarvan is such a good pick against Quinn in 1v1 tournaments, he beats her if he times flag and drag right. However if Quinn saves Vault for when he ults, she beats him, you can Vault out of cataclysm. So really if you think about it, whoever outplays the best wins the duel.
It depends on who uses the move first i believe. When in motion, quinn is actively in a state of dashing until she reaches her target. if Jarven does his move second, he is also in a state of dashing, but since Quinn is targeting a spot behind him, his knock up will take effect first. if he's actually on the way when you activate Quinn's E, you can stop him. it's quite fun (although not as fun as stopping people from taking thresh lanterns. That's an entire game in itself)
