The whole keyboard is usually a little bit off. It comes from the tolerances needed to allow the user (you and me) to "open the hood" and get at the RAM and AirPort slots. Not a problem, but if and when you do open the keyboard, make sure you lock it down again-sometimes it gets a little bouncy if you don't. There's also a bit of electromagnetic shielding in the keyboard that only really makes contact if it's locked down.