Chosen Solution

This seems a little backwards from what my searches have pulled up..

The home button works fine, with the exception of the haptic feedback being a bit finicky (rattle vs the intended vibration) but the Touch ID and, “rest to open” features are non existent.
There’s absolutely no damage here to the home button cable. I did the repair personally so I know it’s the original home button, plus there’s no error message at all. When I boot, or go to Touch ID in settings to register a fingerprint…. nothing … it’ll act totally normal except it just kinda waits there for me to put my thumb down which I am in fact doing, but the phone can’t tell. I don’t understand how it’s possible. They moved from the actual physical button to this imitation. It’s supposed to sense when a finger is on it in order to operate / mimic the feel of a button, and can/does in fact do that with 100% accuracy. Why can it not tell for another feature using the same hardware. I would update but it was fully updated before the repair.. ha I can’t try the old phone screen again, because it’s…. destroyed.. . . And I don’t know the phones behavior prior to the repair because I bought the phone with its lcd already destroyed.
It was a great deal ……

A few possibilities: A really tiny tear on the flex that connects the screen to the logic board. It literally takes almost nothing for issues to pop up because the traces are right up to the edge of the flex.A tiny tear in the actual HB flex (see above)Damage to the connector on the HB flex or on the screen flexDamage to the Turtle IC from lifting the HB flex off the screen. These usually affects the “click” function only. Of course, it could be any combination of the above as well. Despite your best efforts, it’s obvious something went wrong. The iPhone 7/8 series have a very inconvenient bend on the Home Button flex. It’s really easy to tear the flex, either near the logic board connector or at the 90 degree bend before it sneaks underneath the LCD heat shield. You have to be careful anytime the flexes are connected and you have the device open. The long and short of it is that there are multiple failure points. You will need to carefully inspect the Home Button and flex to see if there is any damage. Magnification here will help.  Look for tears to the flex or any physical signs of damage. You should also check the connector to insure none of the pins are damage or that there isn’t any debris.