When I got my iPhone 6s last year, I noticed that whenever I plugged it into power via the lightning cable (all official Apple components from the box), I could feel what felt like an electrical current when I ran my hand along the back of the aluminum case. If I unplugged the phone and ran my hand along the back, the feeling was gone. I've had a jet black iPhone 7+ since it launched and I'm feeling the exact same thing when the phone is plugged in to power, again with the official Apple lightning cable and AC adapter that came in the box. I'm not sure if I just got two phones that have some type of short or defect or if this is how this is supposed to work. The current doesn't shock me or hurt or anything but it definitely doesn't feel right that I can feel electricity when my phone is charging. Is this worth a call to Apple?