I'm back, and I actually found a fix! It was a lot easier than I thought- I essentially just had to slap a "fade in bgm - 0 seconds" command on the end of the "exit the Options Menu" method.
The bug is pretty minor overall, so I'll just ship this with the next update. (Along with a fix to a typo in the Auction House- "Minimum" should not have four "M"s in it.)