USPS recently reported that an estimated 5% — or 2.5 million — of its 50 million Jack-o'-lantern stamps had been affected by a manufacturing defect in the diecutting process.
Banknote Corporation of America (BCA) produced the stamps in August, but the error wasn't discovered until after the initial distribution.
Sandra Lane, BCA’s vice president told USPS,
Stamps with out of register die cuts have been identified as being shipped to the USPS. Out of register diecut is part of the normal process variation and requires segregation. Unfortunately, not all the material was segregated correctly.
The out-of-register diecut resulted in stamps that were of varying sizes on the same panel. From reader-submitted images posted on Linn's Stamp News, it seems that only the bottom portion of some of the stamps were affected.
Printing Perspective: Although USPS reported that the stamps could be used as valid forms of postage, if the diecut had been more significantly out-of-register it could have posed a notable problem, especially if it was on a larger scale. Even though BCA has in-line inspection systems in place, they seem to have missed the error, which highlights the importance of frequent quality control checks to limit inefficiencies and waste.