Insertion point, placement not respected

Thank you for this beautiful mobile menu.

The only issue I have is with its placement. I chose it to be in the navigation bar/main menu, which is on the top part of the page, yet, when I view a client's website on a mobile device, 5.5, vertically", the menu appears at the bottom. Viewing it horizontally works fine.

I have spent some time placing it in different regions of the page, header, navigation bar, content, highlighted content, still, when viewing a client's website vertically, the responsive menu appears at the bottom of the page.

Any ideas on how to fix this? To make responsive menu appear always at the top of the page?

Thanks

Hector