Weird rear brake noise

You could have that area of the drums machine a tad to prevent the contact. Might be able to do it on a brake lathe? The real question is, though, why is it rubbing.....it shouldnt. I wonder if they have the right gasket (s) in the right places. I could be wrong but I think it goes axle housing - brake back plate - gasket and then the bearing retainer. If the gasket is between the back plate and housing you might get the interference.