Comment by unfocused
Adobe Pro, when used properly, will redact anything in a PDF permanently.
Whoever did these "bad" redactions doesn't even know how to use a PDF Editor.
We have paralegals and lawyers "mark for redaction", then review the documents, then "apply redactions". It's literally be done by thousands of lawyers/paralegals for decades. This is just someone not following the process and procedure, and making mistakes. It's actually quite amateurish. You should never, ever screw up redactions if you follow the proper process. Good on the X-ray project on trying to find errors.
I just want to add, applying black highlights on top of text is in fact, the "old" way of redaction, as it was common to do this, and then simply print the paper with the black bars, and send the paper as the final product.
Whoever did it is probably old, and may have done it thinking they were going to print it on paper afterwards!! Just guessing as to why someone would do this.
Or they may not understand how PDF works and think that it's the same as paper.
Especially with the "draw a black box over it" method, the text also stops being trivially mouse-selectable (even if CTRL+A might still work).
Another possibility is, of course, that whoever was responsible for this knew exactly what they were doing, but this way they can claim a honest mistake rather than intentionally leaking the data.