Corrupt PDF after replacing a page or inserting/deleting page

I've been remediating decent size PDFs (anywhere from 10 to 60 MB, usually around 100 - 150 pages) and I keep having an issue where I cannot simply replace a page. If I do, the PDF becomes corrupt. Sometimes I can insert, save, delete, save - but other times that will corrupt the PDF as well. I see that my table structures will dissapear after the replaced page, but not all of the ones behind it are. I cannot see the table summary or headers for any of the tables though.

Looking at Preflight in Acrobat Pro DC 2015 Profiles, listing protential font problems shows that my fonts are not embedded at all. When I go down to embed missing fonts and fix potential font problems and analyze, neither show a problem. I cannot do the analyze and fix because I cannot save the PDF.

For the whole process - I start by opening tiffs in Abbyy FineReader, set box structures, clean up OCR, etc. I then send to Adobe Acrobat and save as a PDF in Acrobat, then finish the rest of the accessibility work. Things are fine until I need to replace a page. Again though, there are times when I can insert, save, delete, and save without any issues - but not always.

I have tried printng to PDF - that created a montser looking PDF and ultimately did not work. I tried combining files, that also did not work. I'm running in circles and often times having to resend and recomplete work. Any ideas????