UnicodeDecodeError: 'utf-8' codec can't decode bytes in position 4-5: invalid continuation byte

[YuGiOhJCJ]

Checklist

• I'm reporting a broken site support issue
• I've verified that I'm running youtube-dl version 2020.03.24
• I've checked that all provided URLs are alive and playable in a browser
• I've checked that all URLs and arguments with special characters are properly quoted or escaped
• I've searched the bugtracker for similar bug reports including closed ones
• I've read bugs section in FAQ

Verbose log

$ youtube-dl -v --all-subs https://animedigitalnetwork.fr/video/naruto/4189-episode-1-et-voici-naruto-uzumaki
[debug] System config: []
[debug] User config: []
[debug] Custom config: []
[debug] Command-line args: ['-v', '--all-subs', 'https://animedigitalnetwork.fr/video/naruto/4189-episode-1-et-voici-naruto-uzumaki']
[debug] Encodings: locale UTF-8, fs utf-8, out UTF-8, pref UTF-8
[debug] youtube-dl version 2020.03.24
[debug] Python version 3.6.2 (CPython) - Linux-5.2.8-desktop-x86_64-Intel-R-_Celeron-R-_CPU_G3920_@_2.90GHz-with-slackware-14.2
[debug] exe versions: ffmpeg 4.1, ffprobe 4.1
[debug] Proxy map: {}
[ADN] 4189: Downloading webpage
[ADN] 4189: Downloading player config JSON metadata
[ADN] 4189: Downloading links JSON metadata
[ADN] 4189: Downloading vostf mobile JSON metadata
[ADN] 4189: Downloading m3u8 information
[ADN] 4189: Downloading vostf sd JSON metadata
[ADN] 4189: Downloading m3u8 information
[ADN] 4189: Downloading subtitles location
[ADN] 4189: Downloading subtitles data
Traceback (most recent call last):
  File "/usr/bin/youtube-dl", line 11, in <module>
    load_entry_point('youtube-dl==2020.3.24', 'console_scripts', 'youtube-dl')()
  File "/usr/lib64/python3.6/site-packages/youtube_dl/__init__.py", line 474, in main
    _real_main(argv)
  File "/usr/lib64/python3.6/site-packages/youtube_dl/__init__.py", line 464, in _real_main
    retcode = ydl.download(all_urls)
  File "/usr/lib64/python3.6/site-packages/youtube_dl/YoutubeDL.py", line 2019, in download
    url, force_generic_extractor=self.params.get('force_generic_extractor', False))
  File "/usr/lib64/python3.6/site-packages/youtube_dl/YoutubeDL.py", line 797, in extract_info
    ie_result = ie.extract(url)
  File "/usr/lib64/python3.6/site-packages/youtube_dl/extractor/common.py", line 530, in extract
    ie_result = self._real_extract(url)
  File "/usr/lib64/python3.6/site-packages/youtube_dl/extractor/adn.py", line 204, in _real_extract
    'subtitles': self.extract_subtitles(sub_path, video_id),
  File "/usr/lib64/python3.6/site-packages/youtube_dl/extractor/common.py", line 2892, in extract_subtitles
    return self._get_subtitles(*args, **kwargs)
  File "/usr/lib64/python3.6/site-packages/youtube_dl/extractor/adn.py", line 80, in _get_subtitles
    dec_subtitles[:-compat_ord(dec_subtitles[-1])].decode(),
UnicodeDecodeError: 'utf-8' codec can't decode byte 0xe6 in position 0: invalid continuation byte

Description

When I download a video on ADN with all the available subtitles of the video, there is an error.
It seems to be a problem with an unicode character that can't be decoded.
I saw several open bugs about UnicodeDecodeError but none at position 0 so I report.
If you think it is a duplicated bug, feel free to close this one.

Is there a workaround or a fix for that please?

Thank you.
Best regards.