controller works fine untill fully assembled or squeezed

im trying to service my 2 xbox elite 1 controllers.
both had slight stick drift, but worked fine otherwise.

i replaced the case on one of them because the rubber was peeling off.
well now i have both of them torn down. and when i test them with batteries and no face plate. they work fine. but if i screw down the face plate it dies, and wont turn back on. same if i squeeze it. it turns on when i plug in a usb, but will also die when compressed.

the batteries are making full contact at all 4 points. and i tried a rechargeable pack that only touches the 2 metal pins that go directly to the circuit board. same result.

any form of power dies if the controller is compressed. ive been messing with these on and off for 3 days, and im out of ideas. does anyone know what i might have done wrong.