One day playing on my server, using the latest version at that time, I was listening to the music. I heard the C418 music playing. Then a new song was playing simultaneously with the other one. It also does it with the secret song update.

I thought that it should play one song at a time.

But it played two (or more...) songs at once.

To get this to work use these steps:
1. Go into creative mode (found out on a server)
2. Listen to the music
3. Wait until the game makes two songs.