Iron Golem attack damage cannot be changed by behavior packs

When i adjust the attack damage of an iron golem in a behavior pack it still deals the standard 7-21 damage.

Steps to reproduce:

download vanilla behavior pack

change the uuids to make it random

change iron_golem.json attack value to something else(eg 999)

import the behavior pack and install it on a new world

notice how the iron golem deals standard damage when it hits u