Audio control in Train Kept A Rollin'

[JohnnyFAS]

Sorry if this was already posted about, but I wanted to say that for some reason if you play Train Kept A Rollin as the singer, you cannot adjust the vocal track volume. You can still adjust your mic volume and instead you can also adjust the guitar volume. It seems someone goofed and linked the volume controls to the wrong audio track. Is this going to be fixable through an update?

Anybody else notice this, or could it just be my copy somehow?