Menu button isn't working on mobile

I’m building a site for a client, menu button seemed to be working fine a couple weeks ago when I last checked. Now when I click the button on mobile the menu doesn’t drop down.

Another change I’ve noticed is now, whenever I click one of the nav items it takes me to the section instantly instead of smooth-scrolling how I originally had it set up

Here’s the read-only:

I’m having the exact same bug…

The menu dropdown and anchor links are working for me in preview mode of your read only link, is this only happening in the published staging site?