Hello JB_72,
as you seem to have local knowledge  about this area, I would ask you to cross check if the access modification  from access=permissive to access=private for the ways https://www.openstreetmap.org/way/96214114 and https://www.openstreetmap.org/way/96214112#map=19/60.221502/25.189176&layers=VN was really correct. I believe that it should be access=customer just like https://www.openstreetmap.org/way/96214117. The private access tag on these two way prevents routers from finding the ferry to Travemünde.

Another option would be that customers are supposed to take these segments: https://www.openstreetmap.org/way/261108165#map=19/60.220281/25.192435&layers=VN and https://www.openstreetmap.org/way/261108164#map=20/60.2211108/25.1933786&layers=VN

thanks
ratrun