Played aroud a bit with settings:
Switched to MP4 instead of MKV and selected only the main language:
- No change in segment count display while downloading
- Video Temp files: 0-276.tmp (at least 211.tmp_tmp seen)
- Audio Temp files: 277-533.tmp (with 366, 411, 430.tmp_tmp)
- Download process get stuck
It seems that tmp_tmp files get removed. I could imagine that this will cause the shift.
The tmp_tmp files seem to have the same content type, at least they start with a similar header.
0-276 -> seem that there were 277 segments first, later 272 files left in video
277-830 -> 551 files including tmp_tmp
Now I got a file which seems to be better.
Perhaps that helps the devs to improve that downloader.