Collection binding results in first collection entry beeing removed

When I use an list item view, which itself is rendered using model binding, the collection happens to delete the first model-view when the corresponding model changes.

I identified this code section (around line 591, in collection.set()) to be responsible for this behaviour:

            if (isModel(target)) {

                // ADD/REMOVE Event (from a Model):
                // test if view exists within the binding...
                if (!views.hasOwnProperty(target.cid)) {

                    // Add new view:
                    views[ target.cid ] = view = new collection.view({model: target});
                    var index = _.indexOf(models, target);
                    var $children = $element.children();

                    // Attempt to add at proper index,
                    // otherwise just append into the element.
                    if (index < $children.length) {
                        $children.eq(index).before(view.$el);
                    } else {
                        $element.append(view.$el);
                    }

                } else {

                    // Remove existing view:
                    views[ target.cid ].remove();
                    delete views[ target.cid ];
                }

            } else if (isCollection(target)) {

As you can see, when a model is coming through the target parameter rather than a collection, it is removed if it's already present in the view list - which is the case for an initialized collection.

This is only reproducible with the first model/view pair in the list - all other list models are updated properly, the event not beeing triggered.

I'm not familiar with the innards but I suppose the event which is triggering the run through collection.set() is probably unwanted or misguided. Removing the isModel() block fixes this issue, however I'd rather prefer to know why exactly it's there in the first place.

Please could you explain this a bit?

gmac / backbone.epoxy

Collection binding results in first collection entry beeing removed #49