Description:
It seems to be related to the Droid Arabic Kufi font in exporting numbers. If I replace it with Liberation Sans, all the numbers export without problem.
But while using Droid Kufi font;
If you look carefully at the numbers, you’ll notice they have a somewhat non consistent shape and colour (like some transparency has been applied). This seems to me akin to some picture embedded in the font so basically the numbers are invisible. Also I selected the text containing the numbers in the generated PDF, and copy-pasted it to Writer and Word, to inspect the formatting of the text. And while the Arabic characters had the “Droid Arabic Kufi” font, the numbers were in Lucida Sans Unicode, which hints that there happened a substitution for characters missing from the font though they were invisible.


 

Steps to Reproduce:
1. I have installed a “Droid Arabic Kufi” that I found somewhere (v.1.00 from Dec 2012) on my Fedora 34; (it should be already shipped in the distribution)
2. Now I opened Libre Office Writer and typed a random numbers using Droid Arabic Kufi.
3. I can reproduce the problem exporting (using toolbar also I tried every single exporting-option existed there), and viewing in “Evince”.
 

Actual Results:
In comparison to the same place in PDF, the numbers seems to be invisible.

Expected Results:
The number should be substituted -after the PDF conversion- in "Droid Arabic Kufi" , also it should be visible.


Reproducible: Always


User Profile Reset: Yes



Additional Info:
Version: 7.1.8.1 / LibreOffice Community
Build ID: e1f30c802c3269a1d052614453f260e49458c82c
CPU threads: 4; OS: Linux 5.15; UI render: default; VCL: gtk3
Locale: en-US (en_US.UTF-8); UI: en-US
Calc: threaded

Also the font used in attachments is “Droid Arabic Kufi” (v.1.00 from Dec 2012)