This issue still persists in the newest update.

Once again Kid, Go hop on the Arma 2 editor and use the addWeapon command for NVGs there. It works. It's not the wrong command. It just adds them to the wrong slot and they need to fix it.

assignItem does work temporarily but the addWeapon still needs to be fixed.

addGoggles and removeGoggles are for the wearable goggles, like sunglasses and stuff. Not Night Vision Goggles, since those go in a different slot than goggles.

That's wrong. I can 'this addItem "NVGoggles"' and it will add them to my inventory, and they do work. I just can't have it added straight onto my head.

Wrong kid. addWeapon will automatically equip it. Go try it in Arma 2. addItem will put it into your inventory without it on.