I am not sure if this is only with Aura, could be with bushwhacker too (or any merc with a deployable)
So, looks like its when you start putting down an object as you die while in mid air and then you get revived. You become that object until your movement state changes. As you can see in the video below, Aura becomes visiable once again not after she plants the healing station but after she stumbles over a bit of collision giving her a few milliseconds of “falling” state.