When I go from my survival world to build in my creative world, one piece of music starts to play, then, suddenly another starts to play at the same time. To my knowledge, this only happens when I open up my creative worlds and affects the game until I close the entire program. Also, the music doesn't stop playing when I put on a music disk. They play side by side. I am playing on a Macbook Pro 13' Early 2015 128GB SSD