When I receive any notifications, text or email, while on a call, the caller will hear a loud buzz if vibrate is turned on. I had my first iPhone 6s four weeks ago. This noise started from the very beginning. I just returned it to the Apple Store and they provided a replacement. The replacement is making the same noise. I can turn the vibrate off and it will not make the noise. Anyone else having the same issue? My previous 5s did not make this noise.