When playing my game on a device (3G) I occasionally get a black screen right after a transition. I can still hear the game sounds so I know it's not a crash, but I can't interact with anything.

This happens infrequently, maybe once every 30 or 40 transitions. The issue never occurs on the simulator.

The only thing I can think of is that I have a timed blink function that flashes menu items several times after they're tapped, but I make sure to cancel out those timers before calling the transition. I will try to post code after work.