I’ve experienced this on a couple of my sites recently.
On desktop only (not a problem on mobile), When you hover over the toggle, the interaction triggers just fine, but when you click to reveal the off canvas menu, nothing happens. However, sometimes, if I scroll to the bottom of the page and back to the top and try again, it will work. This issue occurs on both Safari and Chrome, and does not appear to be the result of a plugin or theme conflict, and there is no additional CSS. Does anyone have any idea what might cause something like this to occur?