I have a 2012 Versa sedan, and the same thing happened to my car. The mounting bolts they use to secure the heat shield have a small surface area, and that causes the metal heat shield holes to fatigue over time and then just fail. What I did was just remove the bolts and install over sized washers and reinstall the bolts. That solved the problem. As for the vehicle itself, we have two Versas, a 2009, and 2012, and they have provided great service with very few headaches.A couple of weeks ago noticed this odd rattle. Over the following week or so it became more pronounced. Brought it to a dealer to look at it, apparently the heat shield around the exhaust has failed.
Basically a weld or mounting or such. They ordered a new shield which just came in today. So they scheduled me for next Monday to replace it.
12,000 miles, sure hope this isn't a sign of things to come. Anyone else experience anything similar? I understand there is always opportunity for random defects. Just hope this is all.