I was playing on a world I had just created (Named "Testing Grounds") it was a Redstone Ready Superflat type world and I had been building a Nuke Machine (Which is a bunch of TNT Minecarts, I hadn't placed them yet either). However, some music started playing, and don't get me wrong, I like the music (Thank you C418), but at that moment I didn't want it on, so I went into Music & Sounds in the Options and put Music to off. After I had finished building, I had noticed the music was still playing, but in a buggy way, as if it was trying to stop and play at once. I once again checked if the music was off and it was. Strange.