You must activate the mod, before entering the maps. Otherwise it does not work.If you activate / deactivate the menu while on the map. The mod will not fulfill its function. At least that is the case in my case. I hope my words are useful. Greetings.
P.S: It also depends a lot on the weapons with which you attack your enemies. For example, with the bow, the enemies will not attack you. They will only stay at a fixed point. On the contrary, with melee weapons, such as the spear, swords or maces, you will still receive some damage. You can tell by the low durability of your armor. Fundamentally with the bosses.