Right, it happens everytime with/without tao armor. It's not a big deal, it's just annoying in kos duels as you can't be at full HP when you warp to pvp. 
Pot a bit to full HP(If the Koser doesnt allow you to tension relax). Alls fair in a KOS war anyway.
@Anni
I currently get over 32K hp only with Tao

Maybe with a different build and different HP gear it happens too. Since I just use Tao for HP - This is the only time I notice it.