My wife and I just were just struggling with putting the button board back in after replacing our right bumper. If you find your face buttons are smooshy or things aren’t lining up right, try this:

The button board has two holes that are meant to line up with two prongs on the piece beneath it. Make sure both are properly situated. One is just north of the thumbstick hole; the other (the one that gave us trouble!) is on the lower left, next to the ribbon cable.