Just walked into Sanctuary after questing for a bit, and got a message that Sturges needs to have an assigned planner's desk, build a new one and assign him to it. Added a packed desk to myself and went to assign him, and workshop mode seems to indicate that he's already assigned to one. Assigned him to the new desk anyway, and got a message that he is now the leader of Sanctuary. Walked across to Red Rocket and immediately got another message that Sturges needs to have a desk and to build him a new one.