That pad is going to be very aggressive on stainless steel it appears. It is likely for a different carbon compound and heat treat rotor. The sintered part of it is nothing new to street pads vs racing pads, but, the heat and heavy metallic of the pad is eating into the rotors. You can clean up the rotor a bit with scotch bright pad and then put the OEM pads back in and run those a few thousand and see if the coloring clears up.