ember-data 3.6 infinit belongsTo fetch

controllers.application.js

import Ember from 'ember';

export default Ember.Controller.extend({
  appName: 'Ember Twiddle'
});

ember-cli-build.js

var app = new EmberApp({
  pretender: {
    enabled: true
  }
});

models.person.js

import Model from 'ember-data/model';
import attr from 'ember-data/attr';
import { belongsTo, hasMany } from 'ember-data/relationships';

export default Model.extend({
  name:   attr('string'),
  parent: belongsTo('person', { inverse: null }),
  child:  belongsTo('person', { inverse: 'parent' })
});

/* 
! Have your inspector open, to see failing request errors. 

Current behaviour:
Running the given code will try to get the parent twice. It returns a 404 twice on getting the parent, and it stops. (Still don't know why it tries twice)
  
Failing behaviour:
Remove the `{ inverse: null }` from the parent belongsTo will cause an infinit loop on getting the belongsTo, even when it returns a 404.

Worked well in ember-data versions before 3.6. Now fails because it uses _scheduleFetch instead of _fetchRecord:
https://github.com/emberjs/data/pull/5671/files#diff-fd4c34d9a34dfde73cd3413128a3c973R1563
*/

routes.application.js

import Ember from 'ember';

const person =
{ id:            1,
   type:          'people',
   attributes:    { name: 'Tom' },
   relationships: {
     parent: { data: { id: 2, type: 'people' } }
   }
};

const server = new Pretender(function() {
  this.get('/people/1', request => {
    	return [200, {"Content-Type": "application/json"},
              JSON.stringify({ data: person })];
  });
  
  this.get('/people/:id', request => {
    return [ 404, {"Content-Type": "application/json"} ];
  });
});

export default Ember.Route.extend({
  model() {
    return this.store.findRecord('person', 1);
  }
});

templates.application.hbs

Person: {{model.name}} ({{model.id}})
<br>
Parent: {{model.parent.name}} ({{model.parent.id}})

twiddle.json

{
  "version": "0.15.1",
  "EmberENV": {
    "FEATURES": {}
  },
  "options": {
    "use_pods": false,
    "enable-testing": false
  },
  "dependencies": {
    "jquery": "https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.js",
    "ember": "3.4.3",
    "ember-template-compiler": "3.4.3",
    "ember-testing": "3.4.3"
  },
  "addons": {
    "ember-data": "https://ember-data.herokuapp.com/builds/737cca348d909fe938d660b74d081062bdb39571/ember-data-3.12.0-canary.0.tgz",
    "ember-cli-pretender": "3.0.0"
  }
}