Did the enemy ships perhaps have emissive armor? I have seen fighters not engaging a target, because they "think" that they cannot hurt the target that has emissive armor greater than the max. damage of the fighter weapons.
I've never used "fighter attack." Maybe it causes them to look for other fighters to attack??? And since there aren't any, they just sit there doing nothing??? I'm just making wild guesses.
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Give me a scenario editor, or give me death! Pretty please???