Using a sweet alert with preventDefault()
I solved this, just in case anybody else comes across it.

Drupal uses a variable called $op == "Update", which is an attribute on the Submit .  When you use preventDefault() this is removed from the Form Data.

The solution is to add this to the sweetalert callback function when they confirm to delete or whatever your use case is.

          formE.off('submit');
          var input = $("&lt;input&gt;").attr("type", "hidden").attr("name", "op").val("Update");
          formE.append(input);
          formE.submit();


Drupal now gets that so hits the form_submit function.