Posted 03/18/2021 5:40 pm
It is not an "error" in terms of the standard error varieties (alignment, offset, overprint, cutting, ink smear, etc.). It is possible it picked up a little ink from the note on top of it. Problem is, the green could have come from anywhere, to include after leaving the facility, so I don't think anyone would consider it an error...although plenty of folks try to sell non-error notes as errors on ebay I suppose.
