From what you're saying, this appears to be a problem with the playback configuration on Brorsoft. The application either doesn't have support for Stereo or it's wrongly configured. There is also the possibility that the software doesn't have a compatible codec to play the file normally, in which case you should avoid using it and pick something else instead.
However, I have decided to test the application myself and it worked normally which means you should update it to the latest version available on the official website.
Secondly, the video file might be corrupted and Sony plays it normally because it renders it differently.