"Same web property ID is tracked twice." — Google Analytics

It's reported as a warning by the Tag Assistant, but it still bothers me.

And this is my analytics.js implementation:

<script>
(function(i,s,o,g,r,a,m){i['GoogleAnalyticsObject']=r;i[r]=i[r]||function(){
(i[r].q=i[r].q||[]).push(arguments)},i[r].l=1*new Date();a=s.createElement(o),
m=s.getElementsByTagName(o)[0];a.async=1;a.src=g;m.parentNode.insertBefore(a,m)
})(window,document,'script','//www.google-analytics.com/analytics.js','ga');

ga('create', 'UA-XXXXXXXX-X', 'auto');

var visited_pages = [];

visited_pages.push(document.location.pathname);

//ga('send', 'pageview');
</script>

<script>
function gaTrack(path) {
    setTimeout(function() {
        visited_pages.push(path);

        ga('set', { page: path });
        ga('send', 'pageview', path);
    }, 1);
}
</script>

It is in the <head></head> tag, as Tag Assistant wants.

I use the gaTrack wherever I do a history.pushState, for instance:

history.pushState(null, null, headnav.data('uri'));
gaTrack(headnav.data('uri'));

And it's all good, nothing is undefined or invalid, but still the warning gets raised in the Tag Assistant.

So my questions are (which may help someone in the future):

Is my approach wrong?
Is my analytics.js implementation and logic inside gaTrack function wrong?
Is there something I could change inside Google Analytics web interface which could slove my issues here?

Solution

If you use google tag manager it will also include google analytics.

thus the compatible way to include google analytics is

  <script>
    window['GoogleAnalyticsObject'] = 'ga';
    window['ga'] = window['ga'] || function() {
      (window['ga'].q = window['ga'].q || []).push(arguments)
    };
    ga('require','ecommerce');
    //etc
  </script>
</head>
<body>
  <!-- Google Tag Manager -->
  <noscript><iframe src="//www.googletagmanager.com/ns.html?id=GTM-XXXXXX"
  height="0" width="0" style="display:none;visibility:hidden"></iframe></noscript>
  <script>(function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':
  new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],
  j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src=
  '//www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);
  })(window,document,'script','dataLayer','GTM-XXXXXX');</script>
  <!-- End Google Tag Manager -->