I got the solution. You can check it at github, https://github.com/videojs/video.js/issues/656
This is the code that you should update on line 6666 and after. Add this code:
if(track.dflt()) {
this.player_.showTextTrack(this.track.id_, this.track.kind());
}
After this: (line 6676, as of v4.3)
this.player_.on(track.kind() + 'trackchange', vjs.bind(this, this.update));
I hope this helps someone.