I have an Xbox One controller where the X button did not work anymore. I disassembled it today, to find the reason for this. It turns out, there is a hole in the motherboard near the X button:
There was this sticker right above the hole (it seems that "XJY" is an abbreviation of "Shenzhen Xinjiaye Electronics Technology Co., Ltd.", which is a chinese company that builds such motherboards):
Now to my question: is it possible that the adhesive of the sticker in combination with the flowing electricity on the motherboard has caused a corrosive reaction, resulting in the hole? I think there is no mechanical cause, since the wires in the hole are still largely intact and the "missing" part of the motherboard was not inside the controller.