It happened to me once when traveling from Nebraska to south dakota, when cutting in and out of 4g to 3g to 1x service. Traveled again last week, and everything was great. There's been a handful of people who have experienced it. Compared to the rest of us, I would say between 1 out of 50 or 100 out of 5,000 have experienced it.
A quick hard reset fixes it.
Ive never even heard of the issue of faint ringing.