ffmpeg always uses simple shaping with "-vf subtitles", messing up Arabic text

[0TTA]

Screenshots

When Arabic subtitles are burned into the video, it does not look as it should

When I use the following command in FFmpeg, It gives me the following result, which is wrong:
-vf "subtitles=test.ass"

mpv:

MPC-HC:

VLC:

Description of the issue

Let's see what exactly the problem is, because if you are not an Arabic speaker, you might not get what the problem is.

This is a screenshot from MPV Player (not burned):

And the following one is the result of the following command (it should not look like this):

-vf "subtitles=test.ass"

libass version

ffmpeg version N-109745-g7d49fef8b4-20230202

Is it a regression?

I didn't know.

ASS Sample

[Script Info]
PlayResX: 384
PlayResY: 288
ScriptType: v4.00+
PlayDepth: 0
ScaledBorderAndShadow: Yes

[V4+ Styles]
Format: Name, Fontname, Fontsize, PrimaryColour, SecondaryColour, OutlineColour, BackColour, Bold, Italic, Underline, StrikeOut, ScaleX, ScaleY, Spacing, Angle, BorderStyle, Outline, Shadow, Alignment, MarginL, MarginR, MarginV, Encoding
Style: Default,Calibri,42,&H00FFFFFF,&H00FFFFFF,&H00000000,&H00000000,0,0,0,0,100,100,0,0,1,1,0,2,30,30,30,1

[Events]
Format: Layer, Start, End, Style, Name, MarginL, MarginR, MarginV, Effect, Text
Dialogue: 0,0:00:01.00,0:16:40.00,Default,,0,0,0,,‫هَذَا اَلنَّصِّ هُوَ مِثَالٌ لِنَصِّ!

Special Fonts

I uploaded or linked to the required font

System Information

Fonts - Copy.zip

Log

No response

Additional info

For more context:
jellyfin/jellyfin-ffmpeg#217 (comment)

[rcombs]

This seems to be an ffmpeg bug where ass_set_shaper is always called with the "simple" shaper when using the subtitles filter (not the ass filter). Please report this to them.