I was clearing named captains from my map - Myrlefsen (more accurately, The Ironclad) is stuck. Please see the video for a detailed view of the problem.
Warning: The video below contains spoilers pertaining to the map and fog of war.
I do not believe that this is his normal location, either.
[ Unrelated to Bug Report: I know he is marked as 'Unaffiliated' - I took some creative license in my video description..... but it does stand to reason that a low ranking pirate would seek to live under the Principi ]