Have you tried pressing the little traffic light icon off then back on? I've seen this once or twice but it was when I was in a dead cell spot that I know my phone cuts out as well.It usually shows I have a connection though, and music will be streaming, but it will still say routing with no traffic data.
I'm hesitant to take it back in because I just got my car back from service again, for like the 8th time. But if it is indeed a real issue then I had better get it back in before my warranty runs out.