Defeated + Revive Orb = Reduced agony resist
If you die enough times, your armor gets broken instead of damaged.
If it is your back piece that is broken, this will prevent you from receiving any AR that it applies to your total.
I’m aware of how broken armor works and how it doesn’t contribute to your stats. My back piece wasn’t broken.
As I said in the OP, the back piece was effectively fused to my character’s back. I couldn’t unequip it despite not being in combat. I was still wearing it and my AR was reduced by 10. My other stats appeared to be unaffected. This is a pretty significant problem with doing a level 40 fractal when fighting the Jade Maw. The only way I was able to fix this was by leaving the instance after we beat it.