Why my s6 edge + does not come up?

[AC Question]

When I don't use my phone for about 2 hours and I try to press its home button after this period, to unlock the screen, sometimes the screen light does not get on, but the buttons on the bottom light up, so I have to press and hold the power button so then the phone come back to the normal state with the display working fine. Is it normal? Thanks for your help.