>UPDATE: > >I went back and reviewed all of the literature on CLS & >Commander Mode (in the "--" double-dash mode): > >"The built-in (pop-up) flash should be turned off. Even >though it is off during the actual exposure, it still sends >out light pulses to control all of the Remote flashes in the >system." > >See, The Nikon Creative Lighting System, 2nd edition, page >223, figure 10.5. > >This indicates that I too have this issue since both flashes >did fire even though I was in "--" double-dash mode >?????? > >Or am I missing something? If I am, someone please let me >know.
I think you misunderstand how it works.
When in the "--" mode, the commander still sends out its command pulses to fire the Remote, which makes the exposure.
And, if you look at the Commander during this process, you will see it fire its flash when the command pulses are sent out. This is a very low power flash, but it is easy to see visually. This low power flash pulse is fired right after the shutter opens, and it will contribute slightly to the exposure if you are very close to the subject.
So, from what you said, I believe your camera and flash are working properly.