Unhappy Phone not waking up properly

Hi,
I update my htc one x to the jelly bean update yesterday. I have been on stock all this while and updated to the official ota. I have not installed any roms yet or unlocked the phone. Since i updated i seem to be having a strange problem. When the phone goes to sleep for prolonged periods, and i try to turn it on, the screen remains black. The light for the buttons turn on and there is light at the btm of the screen but the screen stays black. It has happened twice and the only way to solve it is to reboot the phone. i can hear messages and calls coming but the screen remain black. I am wondering is this a "feature of the phone" or is there any settings i should change? Or is there any solutions to this problem.