Key 'option' is abnormal

The right option key is good. But the left one is abnormal. Even I press and hold, the function of option key works sometimes no.

I always use the shortcut command+option+control+eject to shut down the computer. But because this keyboard issue, sometimes the computer just restart while I want it to shut down. (the shortcut of restart is command+control+eject) And, besides this, option is actually a pretty useful key.

So does anybody else have that problem?

 

Hi, guys. I just wrote an email to jobs. The reply said this is a software bug.
The keyboard will be disabled on certain notebooks for around 10 seconds. But I can't understand that. What's the mean of '10 seconds'? My option key is always abnormal even I hold it 10 sec or more.