Better title would be "impossible RPM," since RPMs aren't a thing that can happen on coins minted after 1989. Starting in 1990, the old practice of punching mintmarks by hand was replaced by making the mintmark part of the hubbing process. As such, any doubling on a mint mark later than 1989 is either a doubled die or not true doubling at all. This one is not true doubling at all. Appears to be Die Deterioration Doubling.