"Alpha" can play during gameplay

If you use the new Credits button, and then exit the credits, all while in a world, the credits music ("Alpha" by C418) will keep playing.

 

How to reproduce:

1. Join any world (including servers)
2. Pause the game
3. Go to Options...>Credits & Attribution...
4. Select Credits
5. Escape the credits using the Esc key
6. The music keeps playing in the pause menu, and then later in the game