I've just downloaded an MKV file with a subtitle track, and the subtitles always appear when I first load the file, and I have to manually turn them off every time which is annoying.
I've tried modifying the header with the Header Editor function in mkvmerge, and I've tried all permutations of the three relevant flags for the subtitle track ('default track', 'track enabled' and 'force display') I can think of that make sense and all to no avail. The settings for these flags in the original file are no, yes and no. Even setting 'track enabled' to no doesn't have any effect.
Any ideas? Or is it a bug?