My Elecraft KX3 has a ping??

This afternoon I was planning on setting up the Alexloop into the living room and try some operating with the KX3. I was wanting to see how the loop worked in the living room. I was going to bring it on the deck but there was the threat of rain. Out of the blue when I was on 15m  in CW mode whenever I keyed a letter and then released the key I would hear a very loud "ping" in the headphones. This only happened on 17m, 10m and 15m. I tried changing the headphones, using a dummy load and reducing the power to 0 but there was always a ping noise heard in my ear? I am not sure if I inadvertently changed a menu option that is causing this. This brought the living room KX3 operations to an abrupt end and off to the internet to see what was going on with the rig. I have posted the question on the Elecraft reflector as well as here on the blog.
Problem has just been solved seems if I have the rig on dual RX and VFO A and B are very close to each other I am picking up "me" on VFO B. Which makes sense and when in dual mod the head phones are split with VFO A in one ear and VFO B in the other. This would explain why the ping was only heard in one ear!