I use boxes like that for other projects and a handy tip you may find useful is cutting off those nubs to allow flush mount. Attaching photos I've done. Dremel cutting blade makes fast work of it...literally seconds.
Thanks guys, I finally got it sorted. The settings and camera angle change didn't fix it so i moved the camera itself and that did it. Apparently it was reflecting off an adjoining painted surface so i moved it 6 inches away from the corner and that fixed it. Thanks again.