Quote:Definition: Isolated
Machine Doubling affects only a small portion of an area without affecting the surrounding features. This affect is most often encountered on the mintmark, since the mintmark is often fractionally higher than surrounding features and thus more vulnerable to impact the retreating die.
As seen here the mintmark was punched in more (deeper) than the details of the coin on the die.
Nice example here, no MD seen on date could very well be fooled by this, please don't try to sell on
as a new variety!...Karma will get you OR, I will have to tell my Foo Bird Joke!