I recently got Ninja Gaiden 3: Razors Edge on the PS3. Ive been having a problem where when i move the left analog stick the top or bottom directional button will also be registered, which means the weapon select will repeatedly appear when i try to move. It doesn't happen after every input but will do this for more than half of my inputs.

Ive tried resetting the controller multiple times but haven't had any results.

Does anybody have any suggestions for solutions?
I can provide more information if necessary.