Hi, It's not a bug, that's how's streamtuner works. Streamtuner will launch the media player, when you click "Tune in" button. The "Stop" and "Reload" buttons are for channel list window, not for controling media player.
You just can't stop the media player in the streamtuner. Maybe you can submit a request to
streamtuner mailing list. But I think streamtuner is just a stream directory browser but not a stream player, it does not make sense if it control the program in it's own UI.