Choppy scrolling using Sticky Navigation

Hi, we are using Sticky Navigation for the menu, and the menu transition is choppy when scrolling. Here are the different results with different options in hopes it will help you trouble shoot better:

BROWSER - Chrome

Transition - Fade:
Scrolling down is smooth
Scrolling up to the top of page is smooth ONLY THE FIRST TIME, after which every time you scroll up the menu transition is choppy.

Transition - Slide:
Scrolling down and back up to the top of page are smooth ONLY THE FIRST TIME, after which the menu transition is choppy.

Transition - None:
Scrolling up or down is always choppy.
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BROWSER - Safari

Transition - Fade:
Scrolling down and back up to the top of page are smooth ONLY THE FIRST TIME, after which the menu transition is choppy.

Transition - Slide:
Scrolling down and back up to the top of page are smooth ONLY THE FIRST TIME, after which the menu transition is choppy.

Transition - None:
Scrolling up or down is always choppy.
- - - - - -

Our website address is wrkmash.com
I've set it at Slide right now for you to test, but I can set any other options any time, or can give you access WP Admin if that helps.

Thanks.