>> But like the PDF with the HTML on it--no one even looked at the output. No developer, no QA, no test users. Or if they did, they didn't care. They just shipped it.

Or it was fixed, but not commited

The fix wasn't the right fix, or applied to the right place, because the bug report was bad

The fix worked on the tester's device

It worked, but was broken by another fix

It wasn't checked again after it was 'fixed'

etc