I wish I did. It's a pricy specialty cable from Paramount. It is a modified SC-28 with a hotshoe wired in that holds the PocketWizard Plus II transceiver. It works, seemingly so, almost always. I saw this happen 2 or 3 years ago when the weather was similar.
The first time on the SC coast, the dew point was reached as a cool night set in. This time in Cookville, TN it had been misting all day and it started after sunset when it got cool.
I had the flash, PW, and camera protected by a large oven bag, so direct moisture should not be the issue. I didn't notice condensation, so it's just strange.
Scott Chapin Powder Springs, GA, USA Nikonians Team Member