Bengali text not correctly rendered when using subtitles filter

[blubub]

Summary of the bug: In my subtitle file, there is সো text, but it rendered as স text. (in Bengali language). I think this issue similar with this: ​https://github.com/libass/libass/issues/682
How to reproduce:

% ffmpeg -i x.mp4 -preset veryfast -lavfi "subtitles=subtitle.srt:force_style='Alignment=2,PrimaryColour=0xffffff,BackColour=0x33000000,OutlineColour=0x33000000,Fontname=Shonar Bangla,BorderStyle=4,Outline=0,Shadow=0,Fontsize=22,Bold=0,Italic=0,Underline=0,MarginL=5,MarginR=5,MarginV=5'" -crf 25 -c:a copy out.mp4 -y
ffmpeg version 2023-05-22-git-877ccaf776-full_build-www.gyan.dev Copyright (c) 2000-2023 the FFmpeg developers
  built with gcc 12.2.0 (Rev10, Built by MSYS2 project)
  configuration: --enable-gpl --enable-version3 --enable-static --disable-w32threads --disable-autodetect --enable-fontconfig --enable-iconv --enable-gnutls --enable-libxml2 --enable-gmp --enable-bzlib --enable-lzma --enable-libsnappy --enable-zlib --enable-librist --enable-libsrt --enable-libssh --enable-libzmq --enable-avisynth --enable-libbluray --enable-libcaca --enable-sdl2 --enable-libaribb24 --enable-libaribcaption --enable-libdav1d --enable-libdavs2 --enable-libuavs3d --enable-libzvbi --enable-librav1e --enable-libsvtav1 --enable-libwebp --enable-libx264 --enable-libx265 --enable-libxavs2 --enable-libxvid --enable-libaom --enable-libjxl --enable-libopenjpeg --enable-libvpx --enable-mediafoundation --enable-libass --enable-frei0r --enable-libfreetype --enable-libfribidi --enable-liblensfun --enable-libvidstab --enable-libvmaf --enable-libzimg --enable-amf --enable-cuda-llvm --enable-cuvid --enable-ffnvcodec --enable-nvdec --enable-nvenc --enable-d3d11va --enable-dxva2 --enable-libvpl --enable-libshaderc --enable-vulkan --enable-libplacebo --enable-opencl --enable-libcdio --enable-libgme --enable-libmodplug --enable-libopenmpt --enable-libopencore-amrwb --enable-libmp3lame --enable-libshine --enable-libtheora --enable-libtwolame --enable-libvo-amrwbenc --enable-libcodec2 --enable-libilbc --enable-libgsm --enable-libopencore-amrnb --enable-libopus --enable-libspeex --enable-libvorbis --enable-ladspa --enable-libbs2b --enable-libflite --enable-libmysofa --enable-librubberband --enable-libsoxr --enable-chromaprint
  libavutil      58.  9.100 / 58.  9.100
  libavcodec     60. 14.101 / 60. 14.101
  libavformat    60.  5.100 / 60.  5.100
  libavdevice    60.  2.100 / 60.  2.100
  libavfilter     9.  8.100 /  9.  8.100
  libswscale      7.  2.100 /  7.  2.100
  libswresample   4. 11.100 /  4. 11.100
  libpostproc    57.  2.100 / 57.  2.100
Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'x.mp4':
  Metadata:
    major_brand     : isom
    minor_version   : 512
    compatible_brands: isomiso2avc1mp41
    encoder         : Lavf58.29.100
  Duration: 00:00:50.82, start: 0.000000, bitrate: 1863 kb/s
  Stream #0:0[0x1](eng): Video: h264 (High) (avc1 / 0x31637661), yuv420p(progressive), 1920x1080 [SAR 1:1 DAR 16:9], 1729 kb/s, 25 fps, 25 tbr, 12800 tbn (default)
    Metadata:
      handler_name    : ?Mainconcept Video Media Handler
      vendor_id       : [0][0][0][0]
  Stream #0:1[0x2](eng): Audio: aac (LC) (mp4a / 0x6134706D), 48000 Hz, stereo, fltp, 128 kb/s (default)
    Metadata:
      handler_name    : #Mainconcept MP4 Sound Media Handler
      vendor_id       : [0][0][0][0]
[Parsed_subtitles_0 @ 0000018b9ec8ec80] libass API version: 0x1701000
[Parsed_subtitles_0 @ 0000018b9ec8ec80] libass source: commit: 0.17.0-49-g1a599b1db748dfc07df98cd37d8603edb87da2fd
[Parsed_subtitles_0 @ 0000018b9ec8ec80] Shaper: FriBidi 1.0.13 (SIMPLE) HarfBuzz-ng 7.3.0 (COMPLEX)
[Parsed_subtitles_0 @ 0000018b9ec8ec80] Using font provider directwrite (with GDI)
Stream mapping:
  Stream #0:0 (h264) -> subtitles:default
  subtitles:default -> Stream #0:0 (libx264)
  Stream #0:1 -> #0:1 (copy)
Press [q] to stop, [?] for help
[Parsed_subtitles_0 @ 0000018b9ebcb340] libass API version: 0x1701000
[Parsed_subtitles_0 @ 0000018b9ebcb340] libass source: commit: 0.17.0-49-g1a599b1db748dfc07df98cd37d8603edb87da2fd
[Parsed_subtitles_0 @ 0000018b9ebcb340] Shaper: FriBidi 1.0.13 (SIMPLE) HarfBuzz-ng 7.3.0 (COMPLEX)
[Parsed_subtitles_0 @ 0000018b9ebcb340] Using font provider directwrite (with GDI)
[libx264 @ 0000018b9ebea9c0] using SAR=1/1
[libx264 @ 0000018b9ebea9c0] using cpu capabilities: MMX2 SSE2Fast SSSE3 SSE4.2 AVX FMA3 BMI2 AVX2
[libx264 @ 0000018b9ebea9c0] profile High, level 4.0, 4:2:0, 8-bit
[libx264 @ 0000018b9ebea9c0] 264 - core 164 r3107 a8b68eb - H.264/MPEG-4 AVC codec - Copyleft 2003-2023 - http://www.videolan.org/x264.html - options: cabac=1 ref=1 deblock=1:0:0 analyse=0x3:0x113 me=hex subme=2 psy=1 psy_rd=1.00:0.00 mixed_ref=0 me_range=16 chroma_me=1 trellis=0 8x8dct=1 cqm=0 deadzone=21,11 fast_pskip=1 chroma_qp_offset=0 threads=12 lookahead_threads=4 sliced_threads=0 nr=0 decimate=1 interlaced=0 bluray_compat=0 constrained_intra=0 bframes=3 b_pyramid=2 b_adapt=1 b_bias=0 direct=1 weightb=1 open_gop=0 weightp=1 keyint=250 keyint_min=25 scenecut=40 intra_refresh=0 rc_lookahead=10 rc=crf mbtree=1 crf=25.0 qcomp=0.60 qpmin=0 qpmax=69 qpstep=4 ip_ratio=1.40 aq=1:1.00
Output #0, mp4, to 'out.mp4':
  Metadata:
    major_brand     : isom
    minor_version   : 512
    compatible_brands: isomiso2avc1mp41
    encoder         : Lavf60.5.100
  Stream #0:0: Video: h264 (avc1 / 0x31637661), yuv420p(progressive), 1920x1080 [SAR 1:1 DAR 16:9], q=2-31, 25 fps, 12800 tbn
    Metadata:
      encoder         : Lavc60.14.101 libx264
    Side data:
      cpb: bitrate max/min/avg: 0/0/0 buffer size: 0 vbv_delay: N/A
  Stream #0:1(eng): Audio: aac (LC) (mp4a / 0x6134706D), 48000 Hz, stereo, fltp, 128 kb/s (default)
    Metadata:
      handler_name    : #Mainconcept MP4 Sound Media Handler
      vendor_id       : [0][0][0][0]
[Parsed_subtitles_0 @ 0000018b9ebcb340] fontselect: (Shonar Bangla, 400, 0) -> ShonarBangla, 0, ShonarBangla
[out#0/mp4 @ 0000018b9ec8db00] video:9863kB audio:796kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: 0.358626%
frame= 1270 fps=109 q=-1.0 Lsize=   10697kB time=00:00:50.79 bitrate=1725.2kbits/s speed=4.37x
[libx264 @ 0000018b9ebea9c0] frame I:9     Avg QP:16.88  size: 53458
[libx264 @ 0000018b9ebea9c0] frame P:501   Avg QP:23.39  size: 15368
[libx264 @ 0000018b9ebea9c0] frame B:760   Avg QP:25.22  size:  2525
[libx264 @ 0000018b9ebea9c0] consecutive B-frames: 11.5% 23.6%  7.6% 57.3%
[libx264 @ 0000018b9ebea9c0] mb I  I16..4: 47.4% 37.4% 15.2%
[libx264 @ 0000018b9ebea9c0] mb P  I16..4:  7.2% 10.2%  1.1%  P16..4: 13.5%  5.8%  2.5%  0.0%  0.0%    skip:59.7%
[libx264 @ 0000018b9ebea9c0] mb B  I16..4:  0.9%  0.7%  0.0%  B16..8:  5.8%  1.6%  0.1%  direct: 1.0%  skip:89.8%  L0:46.6% L1:42.1% BI:11.3%
[libx264 @ 0000018b9ebea9c0] 8x8 transform intra:52.4% inter:34.4%
[libx264 @ 0000018b9ebea9c0] coded y,uvDC,uvAC intra: 34.8% 25.9% 2.7% inter: 2.3% 2.0% 0.0%
[libx264 @ 0000018b9ebea9c0] i16 v,h,dc,p: 54% 32%  9%  4%
[libx264 @ 0000018b9ebea9c0] i8 v,h,dc,ddl,ddr,vr,hd,vl,hu: 17% 45% 17%  3%  3%  3%  5%  2%  5%
[libx264 @ 0000018b9ebea9c0] i4 v,h,dc,ddl,ddr,vr,hd,vl,hu: 24% 32% 12%  4%  5%  5%  8%  4%  5%
[libx264 @ 0000018b9ebea9c0] i8c dc,h,v,p: 61% 24% 13%  2%
[libx264 @ 0000018b9ebea9c0] Weighted P-Frames: Y:5.6% UV:3.0%
[libx264 @ 0000018b9ebea9c0] kb/s:1590.47

Patches should be submitted to the ffmpeg-devel mailing list and not this bug tracker.