Never having worked in a modern printshop, I cannot understand exactly what went wrong with the printing of the stamp on the right. Besides the question about the pink halftone, the black color is slightly doubled, and the red of the building is slightly shifted to the right.
The pink has the appearance of having been printed by a different plate/screen, but I know this is impossible. So, what has happened here?
The last three scans show close ups of the "pinks" from the stamp on the right.