When I am scrolling back to top, manually or with the button, the menu items are making a small shake during less than a second, then they stop normally.
I am using the menu as header feature, and the image change to smaller size when scroll down from the top, this works good, but when I am going back to the top and the bar grows to a bigger size, then that menu items shakes.
For your info if you want to solve it or anybody has the same issue: if the logo height is 109px or smaller, everything is right, the bug comes from 110px and above.