Mobile menu shows all items from footer. How to remove them?

Site URL: http://www.goodstuff.ventures

For some reason, the mobile menu shows all links that are included in my footer - from  a contact form button, to instagram link !
They are not of course part of the navigation on desktop. 

How can I disable this so the mobile menu shows only the main menu items?
Thanks! 
 

I found myself how to do this, in case other people are interested - here is the answer:
in custom css, add

 

.header-menu-nav-item--external { display: none !important; }