I don't remember the power button being capacitive, just light-touch and easy to press accidentally. It sounds like the switch in yours is either sticking on something or going bad if it's triggering when you're handling the machine. I'd try pressing it hard once (not so hard that you break it, just enough to free it or clear whatever's causing it to stick) and then contact the seller if that doesn't get it working normally. You could also try electronic contact cleaner on the switch but the seller might get cranky about a return if you do that so caveat emptor.