If you view a Divi site and see the menu not properly scrolling or transitioning to a sticky menu you can first try these steps:

1. Log into the admin dashboard
2. Go to Appearance > Customize
3. Click on Header & Navigation
4. Make small edits to the Fixed Navigation option, for example bumping the text size up by one.
5. Save and publish and test to see if the menu is loading properly.

If doing the above does not seem to resolve the problem, another action you might try is removing the CSS class “free-sticky” from the navigation section. This action has fixed this issue in Divi websites that are using the Ultimate Header plugin.