From the Document Properties dialog box, click on the “Fonts” tab, which is circled below. To determine if all of your fonts are embedded in your pdf file, open your pdf file in Adobe Acrobat or Adobe Reader. Jump to Font embedding and substitution - Embedding prevents font substitution when readers view or print the file, and ensures that readers see the text. Open the document in ACROBAT, and then select File. First we need to know what fonts are needed to be embedded: 0. Computer, they'll be able to see the file as you intended it to be seen. Why is it important to embed fonts when creating a PDF? “Embedding fonts”.
I assume this is because it doesn't recognise all the font names (e.g.
None of the fonts are embedded in this PDF, so Okular is substituting.