Visible Collapsing Navbar On Mobiles Every Pageload

[Lee]

Hi, recently when viewing our site on mobile devices or in the mobile view - on every pageload the horizontal navbar can be seen disappearing off to the left of the screen. This happens on every pageload and I would think would be distracting to the visitor because I find it distracting!

Here is a link to a demo website that has the same issue as our site when viewed on mobiles - you can see the horizontal navbar disappear to the left everytime a page loads - does anyone know what is causing this and if so does anyone know how to fix this issue?

https://demo74.leotheme.com/prestashop/leo_liquory_demo/en/

 

I only post the link to the demo site to protect our privacy. Our site has exactly the same issue as the above demo site.

Kind regards,