I just got this message in my current game. My thinking is that this ocurred because the home planet of this trade ship has migrated to another faction. So I didnt find out about it until the trade ship arrived at its destination. (just guesing but it makes sense to me). I am gaining a lot more than I am losing so its not a concern but I wonder... how do I now assign this ship to a planet? Just travel to any current core world of mine (or any colony)? I will try that anyway and report back. Trade is important to me as I have 20-25 trade routes that constitute about 1/3 of my weeky income.