When a corrupted source_pts is encountered in StreamProcessSubpicture:processStream, StreamProcessSubpicture's internal state v is set to >= vptsval.length, causing any decoded subpictures to not be saved (write == false).
source_pts should either be sanitychecked or the internal state should be reset to a known value after a decoding error.
PS. Only occurs when subtitles are decoded together with video/audio.
Potential fix (range check)