iPhone 7 Boot Loop issue with Front Camera/Proximity sensor

I have an iphone 7 that is stuck in a bootloop after screen replacement. The phone was working fine for about 2 weeks, then customer called and said his front camera, mic, sensor, etc was not working anymore. Ive narrowed it down to the proximity/front camera/earpiece flex. When its disconnected phone powers up fine but when reconnected goes straight back into bootloop again. Have tried replacing flex cable with 3 other spare ones, no luck. I'v also tried unplugging the home button extension flex cables without any luck. Tried replacing the screen with 3 others screen as well. The only thing I wasn't able to try is an original apple screen and home button assembly.

I have seen other people experiencing this issue as well on this forum, would definitely like to know what's going on. This looks like software related... is this because of 3rd party screens?

Thank you