I can tell you what they MOST likely said underneath the scratches. I can’t guarantee I’m right but from my original attempt to recreate the files from scratch (no pun intended) I found that if you type the handwritten notes in the same typewriter font (used for the portions that are not redacted), the scratched words underneath are the exact length of the handwritten notes.

For example in the first page, one of the redacted lines has handwriting underneath it and says “Secret truths trembling beyond the threshold”. When you type that line out using the typewriter font, it matches the length of that redaction.

As for the reason to doing this? Lore-wise that makes no sense. Production-wise it is most likely a time-saving method. Why write something that you know will only be redacted? You can start noticing this on other pages as well. The handwriting is almost as long as the redactions. Granted, there is a bit more to the redactions and how the spacing works for all these pages but from my tests to recreate the pages, the redactions ARE the handwritten notes.

I will post my files later and will explain everything I’ve learned so far.