I’ve seen it before where a shop I worked at actually sent people to a customer’s out-of-state location, to sort through a printed job and remove the ‘unacceptable’ elements of it. This shop even had quality ‘count-pulls’ at press throughout the runs, and when double checked and compared later, after the fact, the problems were right there in the press pulls. So as the job was being printed, the press operators were undoubtedly aware of what was happening, but due to the sheer size of the job (and maybe their everyday habits), they probably didn’t think anyone would actually catch the ’defects’.
The job literally just ‘flew through’ production and the QC department (apparently), and out the door it went. No time to do it right, but plenty of time to do it again.