Dots

    After leveling the Vampire Arrows skill, the main skill damage increased, but "additionally consumes the target's 16.0 HP every 2 seconds for 10.0 seconds", the bleeding damage remained at level 1, where I should have been dealing with 208 hp every 2 sec.

    Mainly this happens with damage over time, it is similar in other skills.
    Maybe someone know wht this is?

    Vampire Arrow is unique because the first hit is based on DPS of your Bow or XBow but the Bleed damage is actually based on your main hand weapon. So if you upgrade your main hand weapon you should see an increase