This is slightly tangential but possibly relevant.
There is another alternative to listening on a collection of block models or on an individual block model for the change:_isComplete event.
Example:
this.listenTo(Adapt.course, "bubble:change:_isComplete", this.onAnyModelComplete);
onAnyModelComplete: function(event) {
// event.type === "bubble:change:_isComplete";
// event.target === source adapt model;
// event.value === _isComplete value true/false};
}
Both change:_isComplete and change:_isInteractionComplete bubble by default for all models which extend the AdaptModel.
References: