Integrating Mmenu-js for multi-level mob nav

[Iain-g]

In a Flynt 1.4 site I integrated mmenu-js for mobile nav OK, but am having problems in a Flynt 2 site. I've got it working - I used the NavigationBurger component as a start point and adapted - but get a console error:

Uncaught TypeError: Failed to execute 'removeEventListener' on 'EventTarget': 2 arguments required, but only 1 present.
at FlyntComponent.disconnectedCallback (FlyntComponent.js:48:26)
at mmenu.js?v=f01cbceb:2:12983
at Array.forEach (<anonymous>)
at S.setPage (mmenu.js?v=f01cbceb:2:12968)
at S.<anonymous> (mmenu.js?v=f01cbceb:2:24717)
at S.trigger (mmenu.js?v=f01cbceb:2:5388)
at S._initMenu (mmenu.js?v=f01cbceb:2:6806)
at new S (mmenu.js?v=f01cbceb:2:3146)
at init (script.js:15:5)
at Module.default (script.js:8:3)

The nav works but I get a fouc which I'm guessing may be caused by the error?
Component code is here
Any suggestions greatly appreciated 👍.