Thanks Kolio. Seems it was a good idea to keep this thread alive. Apparently this problem is a lot more widespread than just me. It's a long thread, but worth the read. Very interesting, indeed.
Worse yet, one guy said HTC has acknowleged the issue (but would not provide a source), another guy said HTC stated that the issue was unconfirmed. There seems to be two catagories to the problem. Some folks are having the issue with headphones. Others, like myself, have the problem when in a phone call -when the other person is talking.
I only have 3 days left. With no confirmation by HTC and a pending solution, I (with great sadness) am going to turn the phone back in and port back to AT&T and my old phone. So ends my short lived time with the HTC One.