"TypeError: e.gesture is undefined" in ionic.bundle, line 6917

I posted this issue in another Forum topic, but wanted to isolate a key problem, so this is another version of the post here:
http://forum.ionicframework.com/t/two-issues-with-drag-drop-in-ionic-angular/14815.

Briefly, I’m building an app that needs to feature Drag & Drop as an interaction mode. Specifically, imagine an Ionic Side Menu, containing an <ion-list> of people. Any one of these people in the list should be able to be dragged and dropped into a container, somewhere in the view (but not dropped back into the <ion-list>).

I implemented an Angular Drag & Drop library (http://www.directiv.es/Angular-DragDrop). It seems to work - inasmuch as a ghost image is draggable. But, a TypeError: e.gesture is undefined is thrown, in ionic.bundle, line 6917. Why is this error being thrown, as soon as I click a person in the list and start dragging? More importantly, how to correct this? Since it’s not thrown in the Drag & Drop library, it suggests an issue within Ionic, no?

Any help gladly received. This is preventing moving forward with development, so a quick resolution would be enormously helpful. Thank you!