You may not have enough miles on yours yet. I first noticed, or I should say, my son noticed it when I had a little over 5000 miles on it, it may have been there before that and I just didn't hear it. It is a real faint jingling sound and we only heard it when the stereo/radio wasn't playing.
Funny thing too, is my last trip was about 2 hrs long, and the outside temp was about 80°F same conditions as when I have heard it before, only this time I could not hear it, I now have 9800 miles on it. I will listen for it again before I take it back into the service department.
Hopefully they've corrected the problem and yours is good.