My partner has this problem a lot. The fridge zaps her pretty often (metal door and handle). There must be a metal surface somewhere on yours? Maybe the shelves? Or the stove / oven?
ETA: As a person who occasionally kicks my kitties when I go to the bathroom in the dark, I sympathize. It’s a terrible feeling when you startle or hurt them. Luckily, they seem to know that I’m a clumsy idiot and accept my immediate apologies.