I've had this problem too, but can't say I've fixed it yet. For me, landing the Phantom, powering off the Phantom, powering it back on and the iOSD mini display will return. Obviously this loses a bunch of flight time.
I just replaced the iOSD mini, but have not flown enough to say the problem is gone. laselvasurf suggests resetting the can-bus port, I'm not sure what the entails. However, I have wiggled every connection, unplugged and plugged in everything and nothing triggers the problem. I'm hoping replacing the iOSD solves the problem, but need more flights to confirm.
My fear is it's predicting a can-bus failure and I'm not sure whether that is critical for other control functions or whether it is just for display of telemetry information. If the can-bus is failing what should be replace to fix it?