Share your experience!
Using the camera button to quick launch the camera almost never works without having to press the button a second or third time. Is any one else seeing the kind of behavior?
Boot your phone in safe mode and see if the same thing occurs:
http://talk.sonymobile.com/t5/FAQ/How-to-boot-your-phone-into-safe-mode/m-p/348008#U348008
Rebooted into safe mode and the behavior persists.
Yeah, I saw your thread after I posted my own. Either this problem is not wide spread and maybe hardware related or not that many people use it to launch the camera so they havent noticed.
I know some people iin Taiwan found the same problem.
I thinks it should be a reproductionable software issue...
I´m sorry but i have to say that this problem is still there after updating to 4.4.2 KitKat 
Got factory replacement with 4.4.2 preinstalled - same problem with camera button. Previuos one also had same problem with camera button.