Ionic onGesture bug

I've been using ionic and https://github.com/driftyco/ionic-contrib-swipe-cards for a tinder-like interface and noticed that the following lines are executed twice instead of once.

ionic.onGesture('dragstart', function(e) {
    console.log("onDragStart!");
    var cx = window.innerWidth / 2;
    if(e.gesture.touches[0].pageX < cx) {
      self._transformOriginRight();
    } else {
      self._transformOriginLeft();
    }
    window._rAF(function() { self._doDragStart(e) });
  }, this.el);

  ionic.onGesture('dragend', function(e) {
    alert("ionic.onGesture dragEnd!");
    window._rAF(function() { self._doDragEnd(e) });
  }, this.el);

I am on a pc testing this, so maybe that has something to do with it? I've been playing around with it for a couple hours now and am stuck at where to go from here. Any help is greatly appreciated :)