I’m replacing my damper after the pin connecting the damper to the handle broke. When I removed the damper, I found a flat piece of metal (which I’ve now id’d as the smokeshelf) down at the bottom of the fire back). This didn’t seem right but I can’t figure out what it does or where it’s supposed to go. If I place it where it seems like it should go (see first photo) it fits so loosely that it will just fall back down into where I found it (see second photo). Where does this piece go and what does it do?