This problem has been around since at least the late 1990s. I probably still have the return reciept.
Instead of that mold being tossed, it seems to be the only mold now being used for casting. Probably due to the limited number of foundries casting rotors.
So on a newish rotor, we must look for ones that have the 'hats' machined down.
The fact that big names are still selling defective BRAKE PARTS for decades should give everyone pause when buying any aftermarket parts. Is it really the right part? Does it really fit and function the way it should? The manufacturers and remanufacturers clearly don't care as long as we buy it. This problem with the rotors should have been solved decades ago. Yes machining and balancing cost more and buyers might *****, but its the right thing to do.
:soapbox: