Phone unsync's

I have now had my Prius about 45 hours. Great car. 250 miles averaging 52 MPG. On to my issue...

I have an Iphone 4. I sync'd it up myself before I even bought the car and it seems to work great most of the time. Occasionally at start up it doesn't sync and I have to manually tell it to sync to my phone. The memory of the phone stays, but it doesn't connect. Now in addition it even unsyncs without even turning off the car. I make a few calls and then then a while later I go to make a call and have to reconnect it again.

The dealer says it must be my phone. The phone works fine in 3 other cars including my 2009 Camry, so I doubt it.
I have an appointment with the dealer on Friday, but it would nice to know if anyone else is having this issue and what they did to fix it. You know it won't duplicate while I'm there, so they may just shrug their shoulders.
Thanks,
Al

I tried a search and could not find this exact issue.

 

There were no other phones paired to this car. I did mine myself while I was waiting for the finance guy to see me and it's still the only one in it.
thanks for the suggestion though.