That was it! The Muzio app which I have used for 5 or 6 years must have updated itself and added this annoying feature. I would never have suspected it since this just started a few weeks ago and I have had this app for years. Thanks for your help!
Does anyone have any idea how to disable this After Call feature. The A T & T rep thought it may have come from an App I recently downloaded. The only App I have downloaded recently is Costco.