I’m an Offical Apple phone repair tech. A lot of things stop working once you place new parts in, things that have even thrown me for a loop and made me think I did the repair wrong. I replaced a display, and the vibration and camera stopped working properly. I thought I damaged the haptic feedback motor (That I didn’t even remove) You have to sign into apple’s repair website, and ‘run a diagnostic’ in order to get the vibration function to work again after you swap a part on some models. They all do some weird shit.
Sometimes swapping a camera on a model will cause the camera in app to run at like 3 fps or Face ID will stop working until you validate the parts on their repair site. It’s shit.