Single Publish Internet page Hamburger Menu No longer Working.

Hello

The Hamburger menu for my location appears to now not work for my single publish pages in cellular and tablet mode.

works with most pages – https://kchornclub.org/

does NOT work on single publish pages – https://kchornclub.org/2020/11/09/2nd-virtual-ensemble-holiday-version/

What can I enact to moral this?

Thanks