iPhone 4 iOS 4.1 app switcher/ipod controls freeze phone

[plural]

I'm having a problem whenever I double tap the home button to go into the app switcher and then swipe to the left to access my ipod controls, the phone freezes up sometimes and must be rebooted.

This happens when i go to the ipod control only but sometimes the phone doesn't freeze and i can use the ipod controls.
My iPhone 4 is jailbroken. This problem doesn't happen after a restore, so obviously, there is a jb app/tweak that is causing it.

Is anyone else experiencing this problem?