_unbindListeners() should clear the instance of the event listeners per element

[poteto]

This method clears all event listeners on the window and document (in reality, this mixin has only 3 listeners regardless of the number of Components, because of the way Ember registers event listeners globally), which means if you have >1 Component to watch, after one enters the viewport, it unbinds listeners for all other Components, whether or not they have entered the viewport.