If you double tap vault (like I often do with skills to make sure a cast is registred and properly queued) it will make 2 vaults in a row instead of one, no other skill behaves this way. And vault itself does not queue after another vault while pressed mid-animation, only if you initally double-tap the skill. This is a major issue as I would like to control how many times I vault not to fly away from somwhere and not to run out of stamina.