This is embarrassing for A-net. Were it just a side quest, it would still be annoying that it blocked zone clearing, but this is a main quest line. The point where a significant quest is bugged, and blocks you from advancing the story for a MONTH without repair, is the point where I consider cutting my losses at the $80 for CE, and not wasting my time with a broken game. What a shame – a great game being killed by poor support.
EDIT: Today’s patch seems to have fixed it, I was able to complete the quest.