I have spent probably 7 characters trying to find out if this thing does anything. I honestly feel something was overlooked/not coded. Why is a level 50 breastplate on a leader king mob basically do nothing?

I have had conjurers look at it, fought with it in a dozen different scenarios. Done everything possible.

I'm not sure where to post this because I think its a bug but I'm not sure. Could I get a "not a bug" or "bug" so I can settle my overwhelming desire to know everything but I cannot get this one figured out feeling? Hah!