Attribute modifiers work great when applied to single items. However, say i had a +10 Max Health and a +5 Max Health on a breastplate and helmet, respectively. When I equip one of the items, the health boost is added. When the other is equipped, without unequipping the first, the attribute to be modified is reset to its original and then the second item's modifiers apply, therefore rendering the first attribute nullified. (+10 Max Health breastplate and +5 Max Health helmet. Equip the breastplate and receive +10 Max Health. Equip the second, health boost is reset to zero and receive a +5 Max Health from helmet. End health count at 25, expected count is 35.) The logic is shown below; you can see the health bar change underneath the overlay. This irks me when I attempt to create armor sets with bonuses on each piece and they don't add up like they should. I have tested this with other attributes and it only behaves this way with the max health modifier. I am unsure if it is a problem with the UUID range because i have little experience with them.