Unable to select Mikanikos for Soulbind

Received the quest “Path of Ascension: Artemede’s Challenge” which requires me to defeat Mad Mortimer as Mikanikos in the Ascension Coliseum. However Mikanokos does not offer a dialog option to choose him for soulbind, unlike Pelagos or Kleia next to him who has “The Path awaits you” in their dialogs. This is the second week I have received a quest that requires me defeating a memory with Mikanikos but I am still unable to select him as a soulbind.

Same problem… I want to clear for my achievement …