I beat the Beast of Winter on one of my end-game saves. Then I loaded up a level 6ish party in PotD (different difficulty level as well). I noticed that all of the quests for the DLC were still listed in my Journal. The quests I had completed in my end-game save were greyed out and said completed, while one that I never finished on my end-game save still had the last objective listed as my next objective.
I got up to a higher level yesterday and decided to try a run at it. When I got to the location, the dialog seems to work properly - but only to a point.
The initial camera cut worked when I arrived at the island and it transitioned properly to the narrative parchment screen. After that I went to see Harbinger vatnir. His sermon cinematic never came on, and he won't talk to me. He just gives me the generic popup response - no dialog box.
Unsure if anything can be done to resolve this issue. Wondering if anyone else has the problem.