We are experiencing a strange problem that started about 3 weeks ago. Sometimes, either after placing a call or answering one, our phone keeps ringing in the background. The call we've placed (or answered) connects and we can have a conversation with the other party, but we get an annoying ring (that does not stop) in the background.
This happens about 30% of the time - not every call, but 1 out of 3 calls (incoming or outgoing doesn't matter).
Services we have: Comcast Tripleplay - Xfinity TV, Internet and Phone