Text Drop Outs and Jumbled Text in Client PDF Files

Hello,

I work at a printer as a designer and pre-press tech. We are having major issues with PDFs from a particular client. We are getting text dropping out (missing letters) and jumbled text on some pages of their PDFs. We are guessing that the issue is with a missing font (not embedded), but the problem seems to occur somewhat randomly and not every time. We have explained to the client that fonts need to be embedded, but we need to know what we can do on our end, as we have hundreds of files from them that we regularly reprint.

Here's our workflow:

1. Client creates file with their custom written PDF exporter software. (I believe herein lies the issue! This is a very prominent US company, and they have developed a program that gathers files from various sources and combines them into a PDF. Original files were created in various programs such as Word, Publisher, and Powerpoint. Their custom program also adds a company logo to each of the pages. I know that they have professional programmers that developed and maintains this program, but programmers don't necessarily know print standards. Sorry, I don't know much more about it.)

2. We download the PDF file from the company's custom-created FTP website. Files range between 250-700 pages each.

3. The client sometimes asks for changes to be made to the PDF, such as moving or deleting pages, inserting, or replacing pages. We make these changes using Acrobat 9 Pro or Acrobat DC. Acrobat 9 is on a PC; Acrobat DC is on a Mac. We resave to a new PDF name.

4. Email proof to client. Once approved the PDF is sent to production to be printed.

5. Production opens the PDF in Prisma Prepare. Tab pages are set to print 1-sided and the rest 2-sided. Production saves the PDF from Prisma to the same file, which saves the layout info for printing.

Sometimes the PDF will print with letters missing on some pages, sometimes it prints perfectly. Sometimes the newly saved PDF, when opened again (say, for reprinting or to make changes from the client for the next round of prints), shows up with these missing letters or text that is garbled (random characters). And sometimes, the newly saved PDF is fine!!

We're thinking Prisma Prepare is causing the issue, but we really don't know. We have solved the issue in the past by distilling the client's PDF before making changes and saving as a new PDF, but we now know from research that this is not a very good idea. We have also sometimes flattened the problem pages in Photoshop, then inserted them in the PDF, but this makes for a very bloated file.

We are at our wit's end and not sure how we can fix this or deal with it on our end. This is a very large company and we do not want to lose their business. Any suggestions???