Chosen Solution
I changed an ipad air 2 screen for a customer, original home button transferred.. tried a new screen and its the same problem. So opening the iPad smart cover the iPad wakes up, but when you flip the cover over, and slap it on the back of the iPad the iPad goes back to sleep. I have looked at everything super carefully and no rips or dents or anything, changing the screen still makes the ipad air 2 go to sleep, tried different covers, same problem. any solutions? Update (11/16/2017) Its the magnet near the three screen connectors that are causing the screen to close.
The solution to fixing this issue is shown in this video link: https://www.youtube.com/watch?v=Hzvf1aIs… For the iPad Air 2 replacement screens, they do not come with the smart cover sensor IC’s meaning you will encounter issues with the Smart Cover Sensor. You will need to desolder it from the original screen that was on there (cracked one usually) then solder it to the replacement screen as shown in the video.
