I was able to reproduce a NON working wake from sleep camera button BUG!. Everytime!!!
Plug the phone to your PC via USB, after ZUNE starts, close Zune.
Now while my phone is USB connected, the camera button WILL NOT wake the phone from sleep.
But the camera button will work from locked even if USB connected.
When USB plug is disconected, after a few seconds the camera button will start to work properly again, if not usually a reboot will fix it.
Have NOT tried this process by just using an USB wall charger with no computer yet.
But I can make this Symptom appear EVERY TIME, by using the USB in PC method.
Meanwhile my Samsung Focus camera button WILL work while connected to the USB PC interface at ALL time, from sleep or lock screen.
Please, others with no problems, try thismethod to see if your phones will not wake from sleep via camera button when PC USB connected.
Maybe this can lead someone to a solution or cause.....