Checking some other forums, the discussions were taking place in June. So maybe check your statement and see if there are any notes/amendments.

Someone did post the language and this change will apply to all cardholders. However, if you opened your account between 8/1/10 and 7/31/11, you will still have the 3% cash back at restaurants until your 13th billing period. So you'd still get a full year of 3% but after that, it will drop down to 2%.