Bottom Menu When Responsive

Hi,

I am using the latest version of Twenty Sixteen and also WP.
There are no edits(editing of theme files) done to this theme, with the exception of changing colors, etc inside the theme editor.

I Have one menu in place. Primary menu. This menu shows up at the top of website as it should. When the website goes into responsive mode(mobile phone screen width) it collapses at the top providing a hamburger menu as it should. But it also provides the same menu down at the bottom that is fully expanded(open).

How do I either: Make the menu at bottom be collapsed or fully remove it?

Thank you

-one menu(primary)in use
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