Anything going on here? Probably just MD. Are MD's common in the proof sets? The images are from the 2009 "presidency" reverse.
I have just been waiting for someone to mention this, I have the same strike doubling on my presidency coin from my Chronicles set. I noticed that particular coin was rotated 90 deg. in the holder and upon looking closer I saw the same doubling on E Pluribus Unum and SG. I hope it's not strike doubling someone prove me wrong.
Curiously, on my coin the seperation occurs on the north end of the devices, which tells me most likely machine or strike doubling because of the inconsistancy with dollar's coin. Maybe it's a DDR2?
