My iPhone 7 Plus is overheating after a screen replacement!

My iPhone 7 Plus, as well as some other iPhones have been overheating after a screen replacement and I don’t know why. I’ve tried disconnecting practically everything (earpiece flex, display, cameras, charging port) and nothing has stopped the overheating. The top of the logic board gets so hot it burns my fingers to touch it!

Does anyone have any ideas what this could be?