Sometimes while you are spamming vault key while your stamina is still regenerating your client doesn't do the normal expected vaulting animation, but instead it just moves you to the top of the object without any animation playing.
It doesn't happen all the time, but this might also have to do with the stuttery sprint animation (your client does sprint animation, but server doesn't let you sprint, so it moves you forwards and backwards a bit) that sometimes happens, I saw a ticket about it a while back but I can't find it now. I don't know what keywords were used in that ticket either.
This was tested on TheCommunityZ server. My ping is around 50-75 most of the time and I would guess it was medium pop at that time.
It's nothing major, but there might be some mismatches between server-side stamina and client-side stamina, idk.