Might be old news to some of you, but at this point I think it's most people know how to duplicate items in this game. You might think it would be a easy way to get multiple legendary mods with the duping exploit. I'm here to tell you don't bother, at least for the mod itself.
Duplicating a mod, counts as a single mod. Say If I have 4 Legendary armadillo mods that I duped from one I originally picked up, and I put them all into a single armor item, they only count as 1. So you armor value is much lower than it should be. Remove one of them will also bug out the others. So instead of say +200 armor each, the other ones will now only give you +11. When you sell them, it also only count as one in the rebuy menu.
I'm guessing there is some sort of unique ID assign to each mod in the game, and game game calculates the armor value based on how many different IDs you have.
Duplicating a mod, counts as a single mod. Say If I have 4 Legendary armadillo mods that I duped from one I originally picked up, and I put them all into a single armor item, they only count as 1. So you armor value is much lower than it should be. Remove one of them will also bug out the others. So instead of say +200 armor each, the other ones will now only give you +11. When you sell them, it also only count as one in the rebuy menu.
I'm guessing there is some sort of unique ID assign to each mod in the game, and game game calculates the armor value based on how many different IDs you have.