It may need to be tookin apart and cleaned..... or you can also try reseting it but i doubt that would work..... or you can just try to work that little kink out by pressing the a button for a few moments....
a trick my dad taught me... open it up and look at the gold part where the little chip comes into contact with the button, if those are black, dirtyish, erase them with a pencil eraser. he did it for the TV remote before. swear to god!!! soemtimes theyre not visibly dirty, but give it an erase and it probably will help