Let's say we have a class Room and a class Person with a foreign key to Room. Now I want to create a new person in the room and reload all the people already in the room because adding the person might have changed them for some reason. Therefor I send a POST request containing the new person to

persons/?include=room.persons`

This lead to the newly created person to be included twice, once in the data property of the reply and once in the included property. Even though this isn't explicitly forbidden by jsonapi.org, Ember doesn't like this. IMHO an object shouldn't be included twice in a reply - meaning that this should be fixed on the DJA side of things.