I've followed a teardown guide for my atrix and it seems this failure is really caused by the flex cable(camera, etc) that is exactly behind the serial number sticker. The pressure of the battery breaks the fisical grounding connections of the flex that is located exactly in the upper border of the battery seat plate. It's a fail in design of Moto. I've read a lot and many people blames touch screen digitizer but seem less possible than flex breaking unless hard hitting the screen. Batteries get fat in time and replacements are fatter in fact.
See this
Motorola Atrix MB860 4G Earpiece S...B006FCQCPE/ref=cm_sw_r_udp_awd_AP9LvbFTJJYPB
In the image you can see the golden triangle shaped connection (ground connection to backplate) is linked to the rest of the flex by a tiny strip. This zone is always receiving pressure from the battery and the metal plate (battery seat).
Soon I'll upload real images of my atrix that will clarify my theory.
Sorry about my bad English [emoji6]
