GTM Callback firing multiple times

Question

I've followed the Google docs to add GTM tags to my site. For some reason the call back is firing 3 times, however, I only have this tag on the page.

  window.dataLayer.push({
         'event': 'add_expense',
         'eventCallback': function () {
                             alert('wtf');
                          }
         });   

Anyone have any clues on why this may be?

Answer 1

It could be you have multiple GTM containers on the page, including plugins. You can check to see if the callback is being passed different containers ids:

'eventCallback': function (id) {
                         alert(id);
                      }