I seem to have developed a trading "black hole".
Every freighter that the lines have built makes their way to a smaller colony, and float there.
For example:
Mars has a export demand of 1151 Precious Metals.
Earth has a demand for 900 of the same.
Right now there are 10 freighters floating above Mars w/ Precious Metals, and the info screen says that the destination is Mars.
So they apparently drift there waiting for a demand (as opposed to surplus) to open up.
I also have a freighter drifting above mercury waiting to deliver spices, but interestingly, spices are neither produced or demanded there. Again, its "stuck".
The last freigher is drifting above Titan, again waiting to deliver metals to a colony that produces them.
What gives?