Ya, i have the exact same problem with mine. It a design flaw in all the controllers. The plastic ring is too small to allow full movement of the d-pad. Most will not even notice this until they play a game that requires the d-pad extensively. I tried playing dead or alive 3, and couldn't do a double press left move, because it did not recognize the second pressing of the d-pad to the left; the left extension of the d-pad kept on hitting the plastic ring, thereby not allowing it to initiate the move.
Asinine, ms.....