Join Date:Joined: Jan 2014
Screen on can happen due to software request (for example alarm, phone call etc.) or above mentioned buttons and therefore it could be hardware (some type of short creating signal similar to the button press), so it's hard to say. You could try safe boot, factory reset and killing some apps for software related problem and dial *#0*# to test hardware, but I'm not sure if there is a particular test for those 2 buttons. There are also programs that can tell you what wakes the phone up, but since it's brand new phone you probably want to take it to the service at some point, it is not normal from what you describe.