Was so happy to find out this was an idiosyncrasy and not my considerable girth (239 ish with hydration pack-"Mom says I'm husky!")
Got one of these on a Willmont Labs FU Edition 2015 Nomad C I'm testing. It was creeping on me a bit so I called KS. They said they're happy to provide the Retro-Upgrade gratis. I plan on doing just that as soon as it's too wet to kick up dust in Park City. Another issue I had initially was after adjusting the seat post height to compensate for the 3/4 inch creep I was experiencing, next thing I know, the damn thing wouldn't stay compressed, or when I tried to sit on it at full height, it wouldn't stay up. I called KS again and they explained that with with any height changes, you have to make sure the cable housing from the frame to the bars is taught. I gave it a pull, and it was good to go. KS also explained that with the Retro Upgrade, no housing foreplay was necessary with seat height adjustments. I happened to be hauling down DropKick at the Canyons, hit a jump, double ejected out of both Crank Bros DH pedals (think accidental heel clicker) and landed 225 lbs right on the seat and this thing still works great!
Minor creep, and the cable tension notwithstanding. As soon as the snow flies I'm sending it in for the upgrade. Keep you posted. ALL PUNS!
Link for "Retro-Upgrade". http://kssuspension.com/support/service-and-rmas/