It's probably the maproom attached to the CV of that port. Each CV group needs a maproom attached to it so it can be captured after spawning when its port has been captured. Usually, those CV maprooms are tucked away in some remote location on the map where people generally won't find them, since sending troops to them does nothing.
If the troops were running there instead of the port's maproom, then it genuinely is a problem and that maproom needs to be moved.