I ran into a nasty bug in Jumbled Jam 2: The character unlock screen looped endlessly after I collected all the stars. This continued after I restarted the game and tried to play Jumbled Jam 2 as Toree.
For context, I beat Genesis beforehand (Got all stars/crystals then all A's) and found one CD in the second stage of JJ2 while I was getting all stars for that level. I did not beat JJ2 or play Missions beforehand.