Securing an Artifact

I have followed the tutorial step by step for the Secrets of Azeroth quest line. I just finished the arrows and turned that in, getting the “Inside Job?” part of the Whodunnit? achievement. I went to talk to Tithris, but he doesn’t have anything for me. I have tried talking to him with and without the cap, I have also tried to see if maybe I could talk to him on a couple alts as well, but no dice. Has anyone else ran into this problem or maybe have some tip on how to proceed with this quest line?

I had this issue for days! I opened a ticket and asked on the forums.....but I think I just found out what was wrong: After re-reading the Event Guide for Clue 5: The Torch of Pyrreth and checking each step, it says that Tithris would have given you a "Preservationist's Dispatch." I checked my bags and found it! So the issue was that I had to travel to the Waking Shores to look for the three levers! So, check your bags for that Preservationist's Dispatch!

Without getting too spoilery:
Make sure when you use each 'item' you see a Secrets magnifying glass briefly. If you don't someone else may have been using at the same time and you didn't get credit. Order of use doesn't appear to matter but perhaps that was the issue for me.