Kerbal Space Program

Tested with junior docking ports: I had designed a fuel transfer system using containers of fuel with junior docking ports on either side and would have the fuel containers undock with the carrying vessel and dock with another vessel. The two vessels doing this would be docked together already. The problem I am having is that if I pass them back and forth more than once, I find that the magnetic-pulling ability that docking ports have is inactive. I believe this is due to a proximitry-based magnetic field reset, not one that updates on vessels docking with others. This is why I think I encountered the problem of neither docking port pulling the vessel in after once or twice. The attached craft file is a test vessel of this method.