Since my post ive tried on 3 other characters. The first on picked up the quest from the adventure guide and did 5 in a row with no problems. The second one picked up the quest from the pop up when entering a TW dungeon w/o the quest did 5 in a row with no issues. Both of these characters were 80
The third character picked up the quest from the adventure guide did 1 and requeued with the same group but the quest dropped when we moved to the 2nd dungeon. I then reaquired the quest from the popup. After finishing that run I left group and was 1/5 back in the plague land but the quest disappeared when I walked into Stratholm (service entrance) to hand in the quests I had completed in the earlier run. Queued and entered a third TW and picked up the quest from the popup but as soon as I zoned out of the dungeon it disappeared. I went to Tanaris picked up the quest queued for a forth TW but as soon as it was over and I zoned out the quest disappeared again. This character started at 68 and is no 73 after the 4 TW dungeons. But still 0/5 on the quest.