It doesn't matter. Airworthiness directives and service bulletins are released all the time for things that are discovered decades later. In fact, an AD was just issued in January for the MD-11 Fleet for an uncommanded thrust reverser deployment issue.
I won't pretend to know how the engines are fastened to the wing, but there have been issues with faulty parts, faulty procedures, etc, that go undiscovered for years. Alaska 261 crashed because of a combination of these factors. That was on an 8 year old airplane that had logged over 20,000 hours before.
It crashed due to systemic maintenance and oversight failures rather than individual mechanic errors. The airline had extended maintenance intervals and reduced inspections on critical components like the jackscrew to save costs. Both Alaska’s internal quality controls and the FAA’s regulatory oversight failed to catch these lapses.
I say this respectfully, but you don't really have a clue what you are talking about. It could, in fact, be incompetents or carelessness, or a number of other things. This why there are investigations from the NTSB.
UPS has now grounded their entire MD-11 fleet, for what its worth.