My wife's iPhone still has the problem even after adding a 3rd party case. My iPhone does not have the problem while using the official Apple bumper. Very interesting. Though my wife has never noticed a problem during usage. She is happy with the phone and had no interest in exchanging it when I offered.
Aside from all this negative press, hands down best device I have ever owned. This little sucker is amazingly fast and blows my last iPhone out of the water.