Yes, I get that on the front a lot, even after they've warmed up. Always when I'm braking quite hard at low speeds and almost guaranteed in the cold and wet.
It was a bit scary at first (braking for a zebra crossing the day I picked the bike up and the thing just kept going right across) but it's always consistent and has never felt as if they're out of control when they do slide... just no grip
They're up to almost 5000 miles now and the back has squared off a little - was hoping to get Z6's soon but I'll probably have these for another few 1000 miles