in your example Dennis' answer fixes the problem. I had created my own example and there it did not make a difference (it actually depends on the geometry when Simplify Bends takes effect).
Yes, my first thought was that it is "Simplify Bends". But "Simplify Bends" only makes changes based on "an internal ratio" and my own quick example did not change based on "Simplify Bends" therefore I was asking for the model.
Edit your flat pattern feature (from the tree) and uncheck Simplify bends...