Gift the Cruel (Assassin's Creed: Odyssey)

This cultist is revealed in the quest "Trouble in Paradise". The problem is that this mission appears somewhere in the middle of the game. I have now completed almost everything, there are only two cultists from the Delian Union, including Gift. I don't remember going through this assignment. And now I can't open this cultist in any way, I don't have this assignment either, I just don't know what to do, tell me, please.