This is really strange to avoid problems with the character coding of the terminal I rewrote Hybrid to use an option-file.
Instead of calling:
"/Users/selur/workspace/Hybrid/Hybrid.app/Contents/MacOS/MKVToolNix.app/Contents/MacOS/mkvmerge" --ui-language en_US -o "/Users/selur/Desktop/_2021-09-05@00_34_03_4210__01.mkv" --global-tags "/Users/selur/temp/mkvtags_2021-09-05@00_34_03_4210__01.xml" -d 0 --default-track 0:yes --default-duration "0:25/1fps" --aspect-ratio-factor 0:1.422 --no-chapters --compression -1:none --forced-track 0:yes --no-audio --no-subtitles "/Users/selur/Desktop/test  Ω character.m2v"
Hybrid would then call:
"/Users/selur/workspace/Hybrid/Hybrid.app/Contents/MacOS/MKVToolNix.app/Contents/MacOS/mkvmerge" @"/Users/selur/temp/analysis_01_20_31_675.json"
and the content of the json file would be (UTF-8, without BOM coded):
[
    "--ui-language",
    "en_US",
    "--command-line-charset",
    "UTF-8",
    "-o",
    "/Users/selur/Desktop/_2021-09-05@00_34_03_4210__01.mkv",
    "--global-tags",
    "/Users/selur/temp/mkvtags_2021-09-05@00_34_03_4210__01.xml",
    "-d",
    "0",
    "--default-track",
    "0:yes",
    "--default-duration",
    "0:25/1fps",
    "--aspect-ratio-factor",
    "0:1.422",
    "--no-chapters",
    "--compression",
    "-1:none",
    "--forced-track",
    "0:yes",
    "--no-audio",
    "--no-subtitles",
    "/Users/selur/Desktop/test  Ω character.m2v"
  ]
Sadly I got still the problem that, wehn calling the call manually from a Terminal it would work, but when calling it through Hybrid, I end up with:
mkvmerge v61.0.0 ('So') 64-bit
Error: The file '/Users/selur/Desktop/test
No clue why, wrote Mosu, the mkvtoolnix author over @doom9, may be he has an idea what could cause this.
-> think I found the issue, send you a pm.
Cu Selur