I've had 3 head-units in this same car, all for the same issue. I was told the next model year radio would not work in the car, though I expect it would. Why change the wiring harness if the model hasn't changed otherwise? This current head-unit is doing exactly the same trick. When it is too cold, or too hot out, the bluetooth will fail off. You can cycle the power to it, by turning the car off and on, but that seems a bad idea when you're on the highway(joking, do not do this).

Our 2015 Subaru Forester has a radio problem, when the temp. is below 60 degrees the radio takes anywhere from 10 to 30 minutes to start playing normal. The colder it is, the longer it takes. It has been to the dealer 2 times and they can't find a problem with it, "so it is warm after driving 30 miles. " we've called two more times, with no return call.