Mobile Menu Appears at Breakpoint…then gets replaced by default

I’ve been tweaking my mega menu this morning, focusing on mobile experience, and it was working great. Then all of the sudden, not so much — it stopped coming up and the default wordpress menu comes up on mobile devices and narrowed browser windows.

I changed my breakpoint to 1500px and now see that megamanu is activating in place of the non-mobile version at that point, but it’s in the wrong place because the default wordpress non-mobile header persists, and then when I get to an even narrower breakpoint, it disappears entirely and the default wordpress mobile menu takes over.

Can you please help me figure out what happened and how to fix it?

Thanks,
Greg

The page I need help with: [log in to see the link]