"A retouch of the vertical line in the lower left from line 1 to the bottom, with marks below 'E'"
Leopold Beaudet provided an image of a lower left plate position block of six which clearly identified this position. He also pointed out that the 'smudge on the 2' in the right numeral box is constant.
Note the arc in the left centre margin.
It is quite likely that the "marks below E" that Marler mentions are the faint dots and the curved line in the inner oval below the 'E' of Postage. These 'marks' look very much like a re-entry.