This is a Writer problem. I always have the non-printing characters, like the paragraph marker turn on so I know the formatting in the document I am typing, but every time I click on the export to PDF button, after the process, all the non-printing characters are turned off, I had to go to the Tools>Options, and reset the non-printing characters from there again.
If I use File>Export, or File>Export to PDF, sometimes I same problem would occur, sometimes it does not.
Known problem from "Bug 40482 - CONFIGURATION: Formatting aids - displayed nonprinting characters become unchecked during printing and PDF export"
Thank you for your attention!
*** This bug has been marked as a duplicate of bug 40482 ***