Hamburger menu not opening on mobile site

Trying to open the hamburger menu icon does nothing when using the site for small screens.

Firefox 79.0b9 MacOS
Firefox 68.10.1 Android
Safari Version 11.1.2 MacOS - Slides out, but immediately closes
edit, added:
Chrome 84.0.4147.89 MacOS
(Safari and Chrome used with no browser extensions.)