Chosen Solution

Following the screen repair of an Iphone 6, iphone 5s, iphone 6 plus, and iphone 6s the screens appear to work perfectly; however, the owners of each of these phones had issues several days and in most of the phones several weeks following the repair. The 5s, 6, 6 plus all shut off and wouldn’t power on while the 6s became unresponsive to touch. I have repaired many phones before this without ever having this issue. Is it something I may have damaged during the repair, bad screens, or just an issue with the phone that a screen repair is guaranteed to fail because of some other issue with their devices? Any insight on the matter is greatly appreciated

I would suspect that with such a high failure rate on separate devices that the parts you are using are defective. I would try a screen that you know is from a separate supplier if available and see if the problem persists.