Sticky Menu disappears when scrolling down

Hi Tom,

I really enjoy working with your great theme, but now I seam to have a little issue regarding the sticky menu.

I configured the primary navigation this way: "sticky navi on" + "transition fade" + "hide when scrolling down" is unchecked + "menu item height" is empty.

When loading the page the primary navigation appears. Then I scroll down and the "normal" navigation changes to the smaller sticky navi. So far, so good. But when scrolling a little bit more the sticky navi disappears.

I tried to fix it by adding some CSS to my child theme:

#sticky-navigation {
  position: fixed !important;
  top: 0px !important;
  left: 0 !important;
  right: 0 !important;
  width: 100% !important;
}

The CSS worked and the navi stayed fixed, but it always first disappered and then faded in. In the Chrome Code inspector I saw that (obviously some JS) added inline CSS when scrolling down.

Do you have any idea how to fix this little problem?

I made a video which shows you the issue (the website URL)

It would be great if you can help me :)

Thanks a lot in advance and best wishes from Germany!

Mirko