Just as reported previously in this locked thread, I experienced this same case where the hunter was swinging his crossbow when trying to attack raiders even though he was far enough away to firing arrows at them. He didn’t appear to be doing any damage either. This could be the result of long hours of playing in a single session however, as I’ve seen bugs that only creep in under those circumstances.
Edit 1: I just confirmed later that when they swing the crossbow like a sword, it is in fact doing damage but not consuming any arrows.
v. 0.9.7g Idyllic Valley Vanquisher seed 4AA2576586A