@aidacra it looks like you are right its an “Adobe” only issue. I updated to the latest Adobe Reader DC and on reports that have a Blank Heading/Text in the Bookmark, I could not Save As…
So I tried it with Foxit PDF Reader and works fine.
I couldn’t find the issue on any of adobe’s Known Issues KB Articles. The only known workaround I have currently is instead of Save As… Print it to a PDF Printer OR modify the SSRS Report.
Before:
Error: The document could not be saved. There was a problem reading this document (109).
After:
