I loaded a file from a game that I had run overnight on a Mid size board (3 stars). About 8 hours into this extended match I am in the process of eradicating the final race. As I attack their homeworld, the information panel is showing the world to be heavyly defended, but as I jump in I notice that only a few frigates are in the area.

Strangly enough my fleet starts targetting in directions that are off screen. I zoom out again to see the planet info and as I do I notice what appears to be enemy ships but there outside the map. After play with the camera rotation I notice that these ships appear to be miles above the planet.

Sure enough clicking one of my ships so that the camera follows them, shows that the enemy is indeed above the map. i let this play out for about 15 minutes and in that time my fleet is not able to make contact with the other fleet. And since there is no way to withdraw that many unit (since they will auto select another attacket before leaving the planet) I'm stuck right there.