Unresponsive touch after wakeup, but works after you press on/off again.

Hello everyone of you smarty pants out there.

I recently replaced my girlfriends screen on her iPhone 5, and everything seems to work just fine. The only problem there is, is that when you wake the phone up from sleep, the touch is unresponsive. But if you press the on/off button two times to sleep/wakeup the phone, then the touch works just fine, and there is no problem at all. But when the screen is off for more than 10 seconds it is the same problem again.

I have tried to clean install the phone, and recovered from a backup and the problem still persists.

It is my experience that this isn´t a hardware problem, but rather a software problem.

Do you guys have any ideas?

Info about the phone.

IOS 9.2.1

IPhone 5

Thx in advance

Mike