What boggles my mind is that the company must have been extremely aware of the stringent requirements for the manufacture of these critical parts. After all, even from reading the report we can tell that a significant emphasis was placed on quality control and certification - on paper. But with all these hoops they had to jump through, in the end they still didn't seem to take quality control seriously. In any decent aviation company I've ever worked at, obvious problems, like storing different materials together that are easily confused, would've been noted by someone and reported in a safety management system to be investigated and rectified.
It sounds like this company and its employees didn't understand why all the certification was being required to begin with, as if they were making door latches for garbage cans or something.