I have a 2012 Four with solar roof and upgraded audio. The problem is that the BT connectivity to my iphone4 is intermittent. One minute it will show keypad and contacts and the next it will hide it and if we take the connect option, it asks if we want to delete that phone. It pops on and off as though it had a mind of its own. Of course, it never works when you need it to.
I have a 2011 4 and I have the same problem with my iphone 4. When I turn the phone BT off, then back on, the car will then find it and show the contacts, usually until I stop the car and it has to find it again. The phone does stay connected for me however, just loses the contacts. As you say, it does seem to be random, but I have only had it 2 weeks and am still getting familiar.
Very frustrating...not only loses contacts, but loses connection and won't dial. When a call comes in, it seems to work most of the time.