@heavyodin53 I have exactly the same bug. Sigurd stands at the dock and I am unable to talk to him, I do have an option to knock on the hall door but the door is open and nothing happens. I am around 7 hours in and I spent most of my time exploring and completing the side quests, but now that I am ready to leave the starting area, I cant.

When the quest Birthrights ends the next quest does not begin. I have verified the game files and reloaded several times, even going back hours. According to guides sigurd should appear in the great hall, he does not. He does however show up at the dock after some time but I am unable to speak to him.