Armor values are a bit messy:
A default mcreator armor has got these numbers in the editor (helmet, body, leggings, boots) :
2, 7, 5, 3
I know that because of harvest tiers and minecraft formulas these numbers aren't the same in-game, but the bug is that... I don't know how to explain, but here are the actual in-game armor values of that 2,7,5,3 armor:
3, 5, 7, 2
While a vanilla iron armor is:
I am not saying that the default numbers in the editor should look like iron armor armor values, I am saying that what you set in the mod element editor is totally different to the actual in-game armor.
I don't know if this is a bug or if this was supposed to happen.
sorry for bad English