Continued issue with white spot

Hello, this was a second order of this item. Both orders had to be reorded for white splotches where there should have been solid blue. Your team confirmed our art file was fine, but I'm wondering if the cutting mechanism isn't spaced correctly and the bottom portion of the image is getting cut onto the top of the next mailer. Because the splotches aren't exactly uniform in size but they are uniform in location. This issue won't stop us from ordering from y'all, you do great work, but could we have some followup on whether the issue can be prevented in case this client wants to do another reorder down the line? Out of the last order, even of the reprints we had about 1/3 that did not have the spot.