Quinn can breifly root?

I'd like someone to explain to me why this is a thing. It does not express anything (at least in the tooltip) about Quinn's Vault rooting or briefly interrupting a champion. When I was playing Gnar toplane, I would try to jump at any time, and Quinn would just vault, which would stop and root me. Can someone please explain what is happening here or am i missing something from the tooltip? This is not really balanced considering she can toplane and most engages in toplane are jumps, binds, or pulls to get closer like darius. This just makes it null. I dont have pic or anything but its easy to practice/try in a custom.