Whoah! I missed one!
This "ghosting" comes from the fact that they only changed the black plate to change the price.
Ink is printed in this order...Black, Cyan, Magenta, Yellow.
Due to the length of the run, the area that is ghosted in the cyan plate is because that area is "sensitive" from 200,000(?) impressions on top of that black ink.
Meaning, the blue plate has printed that solid screen on top of an area that *at one time* had black text printing there. When the black text was changed, the blue still printed a "ghost" of the old black text because it made the plate sensitive to ink in that area.
Think of making Easter Eggs when you write on an egg with a white crayon, then dip it in the dye. However in the case of these printing plates, this area will *attract* more ink, instead of *repel* it as on the Easter Egg.