I can see what you mean about the imperfection in the face... but is it that bad?? Not really... remeber Man is involved in the process of chip making! Women were made perfect and don't make mistakes... but when man touches something there will often be imperfections. Kind of like split or uneven edge spots on clay chips... those imperfections let you know they were hand made (in this case the printing). Expecting perfection in 60 cent chips? I hate to break it to you but before long many more will have "marks" as well.
Over the years we have seen many forms of imperfections on ceramic chips. Running dye, color smears or light areas, off centered printing and of course edge spot miss alignment.
If you're that much of a perfectionist then complain and maybe the company selling will try and fix it, but that is far from the worst imperfections I have seen.
Love the design and hope you enjoy your new chips!
Dish soap and a rag for cleaning... if it is still there you can try dish soap and a magic eraser cut into 8 squares and rub the surface, just keep In mind a magic eraser has similar qualities to sand paper, it is possible to damage the design.
Fellow Chipper Ben