Ember, relations, and multiple calls

I have a route with the following model :

model() {
const product = this.modelFor('products.edit');
return Ember.RSVP.hash({
  product: product
});
},

WHen I disclay product.licences it shows all the licence from the product.

If I add this line :

const allLicences = this.get('store').findAll('licence'); 

To get a list of licences that can be added to the product, without even returning it via the RSVP, I end up with all the licence in product.licences.

Why does ember act like that? Des he assume every licence in memory is linked to the product?