I completed the 8-person Raid (and its prerequisites) today, got back to the palace and got the auto-message from Isis, but did not get the "What's a diadem" mission. Is the problem that that character was CR 367? Do I need to try again when the character is 368? If so, do I need to do the entire series or just the 8-person raid? Thanks!
If you've completed the sequence (ow mission, solo, alert, ROE, NU) in order, and spoken to Isis, the mission and OP vendor should just appear when you've hit 368. You should not need to repeat the sequence or any content to get it.
It worked! All I had to do was go back to Death Metal Washington and cash-in the tokens I already had and I got enough gear to get to CR 369. When I got back to the Kahndaqi Palace, both Isis and I lit up! Thanks, again!