[Gameplay] Quinn's Vault Doesn't Jump Back, Briefly Can't Attack (uncommon)

http://i.gyazo.com/05d7437b3a50cc13acffc9d772254fc8.gif

Sometimes Quinn (in human form) Vaults at the target but does not jump back, and is unable to attack or move briefly after that (enough time that the target can actually just walk away, or kill you).

I've seen this bug reported before, but only seen it this once myself. No idea how to reproduce, sorry.