got same problem. it does it when my call requires number prompts. i bring up dial pad and i don' t even get a chance to press anything because the screen starts going on and off and and the lower button flashes on and off very quickly and is dull kinda whight looking. I have had nothing but problems with this thing... problems sending and recieving texts and calls, would not hold charge, touch screen would freeze up. i have called customer care like 4 times recieved new battery and sim ecause nothing else worked even the factory reset. Ad I still had to have the maufacturer exchange it. NOW... the problem with flashing screen, I'm prob just gonna have to spend the money to buy a completely different phone. THIS is such a waste of money and time and patients.