I haven't experienced what you experienced. But, I'm having other BT issues.
I'm using a Blueant X3 Micro headset paired with my 8300. However, there's no real solid connection. I get alot of static in the headset when the phone is right on my desktop next to me. Not to mention many other people telling me that they're hearing themselves in an echo. I, however, don't hear any echo on either party.
Think I'm going to try another branded headset. I hear plantronics worked well (from howardforums). Maybe I'll give that a try.
Maybe bring your handset back to VZ for a replacement...just a thought.
Unfortunately, I already exchanged the handset as well as gotten a new earpiece, the Jabra BT150 which is fabulous except for the aforementioned glitches. Also did the same thing with Motorola HS805. It's such an incredible phone, though, that I can live with it. Great sound. Ease of use, etc. One thing a technician told me was to use the handset for the volume control to help with the echo. Turn the earpiece as low as possible and raise the volume of the headset. Who knows? Maybe it will work for you.