Second quest relic not dropping for Ancient Vows quest.

I was performing the Ancient Vows quest in Keth when one of the required items dropped, in duplicate. When I picked up one, the other one disappeared. I finished the zone and did not get the other drop. I then completed the Lost City and the Valley of the Titans, but the required piece to finish the quest did not drop. I went back and re-did these zones multiple times to no avail. On all my other characters I had both pieces by the time I reached the Valley of the Titans.

I believe that this is a bug because of the first piece dropping in duplicate. I am out of ideas as to how to solve this so I can get the charm quest reward. The Keth, Lost City and Valley of the Titan zones are Level 26-27. I am now level 48 and the item has still not dropped.

The other piece is from Bone Pits. The same relic dropping two times at once is not a bug or a problem.