title: GTM issue with double event created instead of dl push
body: <p>I use this code in GTM , that retrieves a number from another domain and stores it on a dataLayer value, with a dL.push. I want the variable to be available on a specific event. </p>
  
  <pre><code>(function () 
  {
       var callbackMethodName = "adnscallback";
       window[callbackMethodName] = function(data) {
          (function() {
             dataLayer.push({
                'event': 'ga_new',
                "id2": data.uid
             });
          })();
  
       }
       var sc = document.createElement("script");
       sc.id = "script_" + callbackMethodName;
       sc.src = "https://example.site.com/getnumber?callback=" + callbackMethodName;
       document.body.appendChild(sc);
  })();
  </code></pre>
  
  <p>But I already create an event called ga_new (hardcoded, that creates all sort of values on the page) and when this codes run, it creates another event called ga_new, instead of pushing the values on the existing event. This creates issues with the tags as they are double firing.</p>
  
  <p>What iam doing wrong and the push, instead of appending the data, it creates the event again?</p>