This happened to me yesterday too. I have it hooked up to the car nav, so every time I enter the car it automatically connects BT. So yesterday shortly after starting the car the nav screen came on with the name of my wife and I heard ringing. I thought that she called me although I was puzzled by the different ringtone - I thought that it was because of BT.

Anyways it turned out that MY PHONE CALLED HER as opposed to her calling me. The ringtone I thought I heard was the tone that you hear when you call people. So anyways, how do I know it was calling her and not the other way around? While during the call she called me this time for real (we both finish at 5pm) because I saw incoming call so I switched to that call and later cancelled the call that my phone originated.

This is really weird - it is a MAJOR BUG. Hope this will never happen again.