My gf has had her Lucid since release day and loves it, but has been having one major issue. The screen on her phone won't stay on when she's on a call. Like when on a conference call and she needs to type in a passcode, she can't get the screen to stay on to type in the numbers. If you hit the power button, it comes on briefly for maybe a second and then goes black again. I haven't yet found a setting to change this, any ideas?