Ember: TypeError: internalModel.getRecord is not a function

I'm inside a component, trying to add a newly created entity in an action:

var stakeholding = this.get('store').createRecord('stakeholding', {[...]});

var allCarings = this.get('allCarings');
allCarings.insertAt(0, stakeholding);

But I get this error message:

TypeError: internalModel.getRecord is not a function

allCarings is initialized at page launch like this, inside the component:

this.store.find('stakeholding', {[...]}).then(function(data){   
    _this.set('allCarings', data);
});

How should I add my entity to the array properly?