This is unlikely to be a Rhino problem but maybe someone has encountered it and knows what to do.
I have hundreds of Rhino PDFs embedded in an Indesign book. When the book is exported from Indesign everything is fine.
After the book goes through Acrobat’s preflighting (flattening, grayscale) special characters in the Rhino PDF disappear. 60+Degree Symbol becomes 60+BOX. It looks like the special characters are disappearing from the embedded fonts.
Can you send me a simple test file that shows this behavior? I recently logged an issue that showed exactly the opposite, where print would do well and export would mess up things.