Definitely not related to Smart Cruise Control. I don't use it. My experience was in the mountains of Tennessee on vacation.Yes. The manual warns against relying on cruise control going down long, steep grades. And my experience is checkered: sometimes the cruise takes over and shifts down to fifth gear to keep my speed more or less where I've set it; other times my speed just keeps going up well beyond the cruise setting and I have to bail out of CC. I haven't smelled any brakes in cruise control. I think that is a function of "smart" CC.