This might already be known, I just figured it out last night after reading the patch notes:
(!empty($user->lang['QUOTE'])) ? $user->lang['QUOTE'] : ucwords(strtolower(str_replace('_', ' ', 'QUOTE'))):
- Encounter behavior has been changed such that if an encounter breaks and would have reset (and respawned the same encounter), it will now check if it was overpowered or overmatched and, if not, it will instead unbreak and become a viable target for a short period of time. If the encounter is defeated successfully during that time, players will receive all of the original encounter XP bonus and some portion of the loot.
So I had this quest that required me to kill a bunch of Weald Wolves in TS. Now they are fairly uncommon since there are about 5 places they can spawn and those spots can spawn several different mobs.
I found a spawn with 1 Weald Wolf and 1 Weald Wolf Pup that were grouped. I would kill the Weald Wolf, and break the encounter with the pup still alive. I'd run a short distance until the Pup became un-targeted. When I went back, both were re-spawned. So I could repeat the process until I finally finished my quest.
The encounter would have to be grey, or else I think the pup would reset by itself, which I think is the intention of what I quoted.
I'm guessing this might already be known by you folks, but posting just in case.