Guild Wars 2

The Giant Destroyer Troll at the end of “Only Zuhl” jumping puzzle on Dzagonur is permanently buffed with “Determined”.

http://wiki.guildwars2.com/wiki/Defeat_the_giant_Destroyer_troll

Wiki says:
BUG: “There is a chance that the Giant Destroyer Troll will spawn at The Iron Veil frozen lake. If this occurs, there is no way to kill it because it will be permanently invulnerable. If this happens, let the troll reset and it will be killable again.”

What exactly is meant with “reset”? Because getting out of fight and loosing all aggro didnt help.

Try guesting to another server, they might have a working boss.