Mechanics of Temporary Vitality Gains Mid Combat

[jpsssss.7530]

I've been playing for a while, but due to me mostly playing WvW and PvP, I was wondering how temporary vitality gains work as a mechanic mid combat. For Example Weaver gets a vitality gain while attuned to earth and Firebrand get some with quickness.

So mechanically, I'm curious more about what happens when the conditional gains drop. Does anyone have any idea what specifically happens?

[Asum.4960]

Both with temporary Vitality gain and loss your % of HP stays the same at the time with the increases and decreases.

So if you are at 50% of 11k max HP and you gain 250 temporary Vitality, you will go from 5500/11000 to 6750/13500 (effectively gaining 1250 HP in this case, but still being at 50%). If you are at 10% by the time the temporary Vitality runs out, so 1350/13500, you will revert to 1100/11000 (effectively losing 250 HP in this case, but remaining at 10%).