I found some issues with medium barbettes.
First, they seem to be using the attachment point intended for the "standard barbette for secondaries" and "tall barbette for secondaries" instead of the normal hull attachment point. That might be intended, but it seems wrong.
Second, they also PRODUCE that same attachment point. As a result, players can string medium barbettes indefinitely.
Third, if you use a medium barbette to produce another attachment point for a medium barbette, then add a second medium barbette flipped 180 degrees, then remove whatever thing originally provided the attachment point for the first barbette, the barbettes will now be using each other as their attachment points, which causes "exception: mount transfer hang" and allows them to be moved freely.