[thejeff]

The most likely explanation is, as Psycho said, the first guy in the squad couldn't shoot for some reason. If the first guy doesn't have a ranged weapon, the AI thinks the whole squad doesn't and sends them all to close.

He may have lost an arm. Rage may have the same effect, but I've never seen it.
In fact, I don't think I've ever seen it except at the very beginning of battle, so it may only check once?