Headphones

I have Moondrop Blessing 2 Dusks. In any Over-Ear it seems like my hearing is even between my ears, but in my Blessing 2 Dusks it seems like the left side is ever so slightly quieter. Since I got my higher end headphones, I've been to a good few metal and metalcore concerts without protection.

So I guess I'm just wondering if maybe my IEMs are showing the hearing damage I may have caused better than Over-Ears do, or if my Dusks are bad or broken? I've had them over a year, possibly closer to 2. They aren't used all that often, and I don't remember whether or not they've always been like this.