This assembly mistake happens when a sewer places pins incorrectly, causing the fabric layers to shift, pucker, or misalign along the seam line. It often results in mismatched notches, uneven hems, or distorted ease. The error forces the operator to unpick the seam, realign the pieces, and sew the section again.
Heard on the job
I have a bad mispin on this side seam, so the waistline notches are off by half an inch.