Someone is Going to Notice
More often, we do some things secretly with the notion that no one will notice. So, instead of doing a perfect job or correcting a mistake, we let it slip hoping that no one will notice. This may be what was running through the mind of the one who made these sketch pencils.
Did the person who sharpened these pencils not realize who buys their stuff? Their customers are mainly artists whose job it is to pay attention to the tiniest of details. There’s no way this huge error could’ve made it past an artist’s radar unless they’re bad at what they do—sort of like the person who sharpened these fancy pencils.