What I can say it's an incompatibility between the video cut with VLC and mkvmerge.
I'd say VLC produces somehow broken output (mpv shows 1000.000fps, MPC-HC shows 48 fps while the video is actually 24 fps - this isn't normal in any case).
Transcoded video itself is OK, but the playback hangs AFTER processing via mkvmerge (used to attach audio / subs streams).
Possible solutions:
1. do not cut video with VLC ![]()
2. do the final muxing with ffmpeg rather than mkvmerge: set code.tools.use_mkvmerge = false in SVP's All settings --> in this case this video works after transcoding
but keep in mind that mkvmerge usually works better than ffmpeg