Hamburger Menu disappeared | WordPress.org

My hamburger menu on tall.org has disappeared. I’ve read all the support articles and have already performed the following tasks:

1. I have disabled all plugin’s and re-enabled them.
2. I’ve validated that the widgets are the same on a page that works – vs – a page that is missing the hamburger menu. On members.tall.org – the hamburger menu works fine. There is no plugin that was used – the theme added the hamburger menu. However, with the same conditions and same theme being used – tall.org will not display the hamburger menu.
3. I’ve cleared my browser cache multiple times – and – I’ve deleted the cache internally with the WP CACHE plugin..

Even after doing all these tests – according to previous articles in this forum – hamburger menu is still missing.

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