I have an iPhone 6S Plus and for the past couple of weeks every time I receive a call and answer it, about a 1/2 an hour to an hour later I get a missed call notification for that call and shows up in the call log as a missed call. This has happens for every call I answer. I asked a few of the callers and they said they only called the one time. Anyone ever experience this? The phone doesn't ring twice, just the once but it still says missed call later on. I don't get it.