Unable to unlock achievement, used tracker to do ALL quest related to Gjalerbron, even hidden ones, and still nothing. GM told me to reinstall wow, did it, repair, did it. The achievement doesnt work.
It looks like the missing quest is supposed to start from a quest item dropped by Necro Overlord Mezhen. According to this WowHead comment, it doesn’t always drop on the first time you kill Mezhen and sometimes requires a second kill. Which would be a genuine bug if it were true.
On the other hand, there are some discrepancies in how WowHead connects the achievement and the quest. It does show “The Scourge and the Vrykul” as the criterion, but the quest ID actually decodes as a different quest (“The Frost Wyrm and its Master”), and “The Scourge and the Vrykul” seems to not exist in the quests database. If this discrepancy is accurate, then the achievement may be impossible to achieve (which would be a much bigger bug).
Hopefully a developer will start looking at this.
I have spoke with multiple GM about this and they dont seem to care. I have done all they say and theyre always Do this do that, but nothing work. ANd WoW head need an update also, multiple time i had to google as to why an achievement wasnt working and find out i was missing a quest somewhere.
A GM can’t do anything until a developer analyzes it and comes up with a GM fix action, if they decide to allow the GM to intervene. Sometimes the devs are content to leave it broken until they release a patch that fixes it.