I don't know about the bug. Even while the thing was working, the gunnery role was not really fun. It felt like everybody involved had only half a ship available, for the very reason that this is exactly what is happening: you can do only a part of what you could do if you used the ship yourself.
So while i can't tell if there currently is a bug or not, my advise is to rather use a ship with SLF hangar. That way, you fly your ship and your friend uses the SLF. Everybody has a fully functional ship, and the SLFs pack quite a punch for their size, to they actually do contribute to the fight. In my eyes that's the only fun way to use multi-crew.