General touch screen incompatibility for iPhone 7 Plus

I work in a large independent repair chain and we have experienced an incredibly large amount of iPhone 7 Plus’ coming back with touch screen issues.

We have changed the screens once again and the problem persists. We then put on the original screen and there is no problem at all.

The problem can sometimes be seen right when the screen has been changed and other times it takes weeks before it shows up.

We are always using OEM quality parts or higher and we have tried 4-5 different previously reliable suppliers. All suffer from the same issue.

Which have now led us to think that the problem doesnt entirely stem from the screen.

I have heard that a cause could be that Apple has used different suppliers for the screens and that the phone only will be compatible with the same brand screen that it was ‘born’ with.

It should therefore be possible to identify which screen would be compatible with the phone by comparing the serial numbers on the backside of the LCD’s.

This is all just speculation so far.

Can anyone confirm or debunk any of this?