It is push doubling altering the mint mark, pushing it to the east direction. Just Machine Doubling. Look at the center of the mintmark. Then compare it to a normal mintmark for that same year. The machine altered it. Not a RPM.
Ok so just a form of Machine Doubling... didn't know that could happen only on a mintmark. Usually I've seen Machine Doubling affecting many letters/aspects of a coin - good to know, though, thank you!
Machine Doubling can vary. Depends on what occurred after the strike. Sometimes a slight, minor, strong bounce can happen, affecting the level of MD. Surface, mid, higher devices can be affected. Also swing can affect direction/directions can create strange MD. Strength also is a factor on MD. With MD doubling there are no set rules that apply. mMD can be different from strike to strike. The machine causes the damage. On a RPM, it is on the die. Not caused by the machine. MD can happen as easily on a variety coin. The machine causes the issue. The die creation creates a die variety. Again note the shape of the mintmark. The left side is the affected side. This maybe a coin contact damage issue. But it is not a RPM.