Why font is changed automatically in LibreOffice for Linux?

I’m using LibreOffice 6.1 on Linux Mint 17. I would like to create a presentation using Impress. I set the font to Droid Arabic Naskh. Then, I save it as .pptx and close the file. When I open it again, the font is changed automatically to DejaVu Sans. This issue doesn’t happen when I save the file as .odp. Is it a bug or something? How can I solve it? I’m writing in Arabic language.

A naive question: is Droid Arabis Naskh present on your computer? Otherwise, LO applies internal substitution rules, the effect of which you see only on next relaunch.

It sounds naive for you but it’s important for me because I just migrated from windows. I think seeing this font on the LO list means that it present on my computer, right? or should I somehow install it?

BTW, I think it’s not a font issue because when I save it as .odp file, the font retains. But when I save it as .pptx file, the font is not saved.

The naive in @ajlittoz’s comment was applied to the question that ajlittoz asked, not to your question: ajlittoz wanted to rule out some trivial, but still possible cause, that is why that naive question about presence of the font on your computer was asked to you. You didn’t mention in your question that you selected the font from available fonts list, which was the reason for the suspicion.

Please file a bug report to our bug tracker, attaching an ODP which uses the font, and which loses the font information when resaved as PPTX.

I did report it as a bug, here’s the link:

I hope anybody gives me a temporary solution until this bug is solved.