So when you have commandos on hold fire, they will not shoot.
However the moment the concealment strike bonus appears, they will shoot even with hold fire on. I'm not sure if this has been reported, but this has happened to me too many times. At first I thought, ok maybe I mis clicked or didn't have hold fire on, but after recording my recent games, I've noticed it's concealment strike bonus that makes commandos shoot regardless.
You can see it here in my clip.
Very first seconds they're concealed, the moment strike bonus appears, they start shooting from very long distance. It's annoying because you need to get up close with commandos and the moment they shoot from max range, your plans go to ruins...most of the time.
After attempting to replicate the bug, I manage to showcase it.
This video pretty much proves its bugged
After further more testing, I found the actual problem. Reinforcing the squad while on Hold Fire, the new members of the squad do not have Hold Fire activated. To quickly fix this, you just need to Turn on and off hold fire and they'll work as intended.