It appears that my fairly new Treo 650 has adopted the annoying habit of thinking my stereo Sedio headset is connected even when it is not.

This, of course, means that I cannot hear my caller, nor can he / she hear me. Also, with the headset connected (as the phone thinks it is) you cannot switch to speakerphone mode (this was my clue as to the problem).

Anyone else experiencing this problem?