Thanks for posting about this! I took a look at your site and tested a few things. It looks like the issue is also affecting a brand new navbar when added to the site. After some more digging, I found the source of the weird menu glitch is from the custom code on your home page:
Once this code was deleted, the menu worked as expected. You may need to refactor that code.
On an unrelated note, I also noticed there is some horizontal scrolling from the absolutely positioned images. To resolve this, you can set the sections of your home page to
overflow: hidden (GIF). You may need to move around some of the images that hang outside of the sections so they don’t get cut off completely – moving them to different sections should do the trick.
Hope this helps!