NPC's gaining all of their health back
This is a common mechanic in MMOs, every mob is designed to stay in his designated area, if you pull him too far away from where you found him he will return back and reset (restore health back to full). This mechanic is in place to prevent manipulation of mobs in certain areas and to prevent many different ways of exploiting and grieving other players, imagine someone pulling hundred of mobs and kiting them back to starter areas.
Problem is that I’ve seen this bug happen even when the enemy hasn’t moved much at all from their general area. Even if my Warrior goes in and hasn’t moved a bit the enemy will just up and start walking away at a slow pace and start regenning health. If this is not a bug, but a feature, it’s a rather silly one. All it does is make you want to use a ranged attack to finish them off, or just use ranged to start with.
The champion rotten Oakheart in Queensdale in an example of a particular case of npc that resets if taken away a ridiculously small distance (you have to circle it on a 1000 range of its spawning place to solo it).
But, besides particular cases, the mechanic is working as intended, as it should, and this is in no way a bug.
It’s an anti-kiting mechanism.
It may just be my perception but it does seem to me that there’s something strange about the way its implemented in GW2. Instead of the mob checking regularly, it seems to wait till you’ve nearly defeated it before deciding it can’t be bothered to die just yet.
lunawisp was my peacebringer on City of Heroes – she lives on in memory as my gaming id.