track header flags of MP4 file not honored
All of the sudden, I have started seeing all audio tracks as default audio track when opening a .MP4 file with more than one audio track. When using ffprobe, only the correct audio track is makred as default - so it's not in the .MP4.
When choosing otherwise and mux'ing the MP4 into an .MKV, only the right track is shown as being the default audio track. But why the incorrect flagging when opening a .MP4? I have tried deleting mkvtoolnix-gui.ini - that didn't make any difference.