JeppView uses different proprietary fonts in its charts. If they are not embedded when the chart is saved to PDF, lettering will not display correctly.
On a Mac, running in the terminal
strings ~/Desktop/vfr_chart.pdf | grep FontName
returns the names of these fonts:
/FontName /FNTSBS+FT-7-Jeppesen-Proprietary-Y
/FontName /FNTSBS+FT-3-Jeppesen-Proprietary-U
/FontName /FNTSBS+FT-5-Jeppesen-Proprietary-W
/FontName /FNTSBS+FT-4-Jeppesen-Proprietary-V
/FontName /FNTSBS+FT-6-Jeppesen-Proprietary-X
/FontName /FNTSBS+FT-13-Jeppesen-Proprietary-C
/FontName /FNTSBS+FT-80-Jeppesen-Proprietary-N
/FontName /FNTSBS+FT-79-Jeppesen-Proprietary-M
/FontName /FNTSBS+FT-77-Jeppesen-Proprietary-Y-B
/FontName /FNTSBS+Arial-BoldMT
/FontName /FNTSBS+FT-11-Jeppesen-Proprietary-A
/FontName /FNTSBS+FT-1-Jeppesen-Proprietary-S
/FontName /FNTSBS+FT-3-Jeppesen-Proprietary-U
If these fonts are not installed on another computer, some lettering will not be rendered correctly, as your PDF viewer will attempt to use the next best fonts. I have not had any luck with manually installing these fonts on computers that do not have JeppView installed, so I instead recommend:
Always embed the fonts when exporting charts to PDF. The tool that comes with JeppView is NovaPDF. When printing (=exporting to PDF), toggle the option "PDF/A-1b" in the dialog window. The resulting PDF charts will display correctly on any device: