Retreating Fighters?

[Barronosod]

I scanned the forums to find the answer to this one, but it might be slightly different than previously addressed issues.

I have a fighter group of about 210 fighters, a mix of rocket designs and beam designs. They're fully supplied and ordinance. They have no orders. When I move them to attack an enemy fleet, they retreat instantly. Oddly, at one point I tried removing 5 random fighters from the group, and then the remaining task force did attack.

Any thoughts?