I had the same problem. I use elementor’s menu widget, referencing the menu which is assigned as “primary menu”. Everything works but the javascript error appears, expecting an element with id “site-navigation” – which is not present in the DOM. After the mention by @shariqkhan2012 I removed the “primary menu” check and the error disappeared.
That theme’s code should check for the existence of the ID before chaining the next statement, but for now, it’s easily fixed (once you know…)
