Did you know that Adobe is not the owner of PDF? Adobe initially created the PDF format, but since it has been taken over by ISO. Adobe only creates tools around PDF (Acrobat Reader, Acrobat DC and Acrobat DC Pro) and different programs that export or write PDF files. So, whatever you have created in whatever program that is not from Adobe does not really concern Adobe.
This said, could you check if the font is embedded? If it is not embedded, is it on the target system installed? If you answer both of my questions with no, you have isolated the cause.
If not, someone needs to dive deeper into the file.
ABAMBO | Hard- and Software Engineer | Photographer