Just noticed that the file size of my pdf was much bigger than yours so I checked my pdf export options (attached).
When I choose "JPEG compression" or "Reduce Image Quality" I get formula errors in the pdf - although they do not look the same as yours, rather than Arabic characters I get a rectangle character appearing in numerous places.
Try replicating my settings and seeing if you still have the same problem.
Just noticed that the file size of my pdf was much bigger than yours so I checked my pdf export options (attached).
When I choose "JPEG compression" or "Reduce Image Quality" I get formula errors in the pdf - although they do not look the same as yours, rather than Arabic characters I get a rectangle character appearing in numerous places.
Try replicating my settings and seeing if you still have the same problem.