Ran into an issue- Don't leave a Companion at the Boston Airport settlement, they seem to get stuck into the walls behind the work bench. Thank heavens I made a custom save 25 minutes before acquiring this settlement, or I would have lost 300 lbs of junk and weapons I had stored on a certain Follower. My quick and auto saves were past this point.

Also left more than 1 follower at Oberland Station, and one seems to have gone missing.. So just be careful where you leave your Followers, not that you can avoid an unforeseen problem anyways.. Just leave them where you already know they'll be safe