At first I thought this was about this site here, discourse.cakephp.org and didn't understand what the OP was talking about.
But today, as I was using book.cakephp.org, I realized he's referring to the way the red header drops in as soon as you try scrolling upward. It's really annoying and not very useful.
I agree: please kill that behavior. The sticky nav bar is plenty. If you must give people quick access to the red position when they're already scrolled way down, make it a widget you can click/tap in the sticky nav that only then reveals the whole header.