Check out my thread here :
https://forums.macrumors.com/threads/1101312/
Actually here you go :
Recently I had been noticing at times that sometimes I would have to tap the home button twice for screen to wake up. I thought maybe I was imagining a click the first time so I didnt think of it much but it happened again today while i was paying attention.
I then googled and found this post :
Unresponsive home button taps. Like others have implied, this appears (to me) to be a hardware issue that I can reproduce. Looking at the home button like a clock face, if I take a fingernail and press at the 12:00 and 6:00 positions on the very edge of the button, I get failures more often than successes. Note that this is not true for the 9/3 o'clock positions, they appear to make contact.