pushPayload issue

models.foo\.js

import Model from 'ember-data/model';
import attr from 'ember-data/attr';

export default class extends Model {
  @attr name;
}

routes.application\.js

import Route from '@ember/routing/route';

const fooJson = {
  foo: {
    id: 1,
    name: "One"
  },
  _foos: [{
    id: 2,
    name: "Two"
  }]
};

const server = new Pretender();

server.map(function() {
  this.get('/foos/1', function() {
    return [200, {}, JSON.stringify(fooJson)];
  });
});

export default class ApplicationRoute extends Route {
  async model() {
    // Swap these lines to see the difference in behaviour
    this.store.pushPayload('foo', fooJson);
    // this.store.findRecord('foo', 1);
    
    return this.store.peekAll('foo');
  }
}

serializers.application\.js

import RESTSerializer from '@ember-data/serializer/rest';

export default class ApplicationSerializer extends RESTSerializer {
  normalize() {
    console.log('***** normalize');
		return super.normalize(...arguments);
  }
  
  normalizeResponse() {
    console.log('***** normalizeResponse');
    return super.normalizeResponse(...arguments);
  }
  
  modelNameFromPayloadKey(payloadKey) {
    console.log('***** modelNameFromPayloadKey', payloadKey);
    
    if (payloadKey.charAt(0) === '_') {
      // Uncommenting this line fixes the problem
      // payloadKey = payloadKey.substr(1);
    }

    return super.modelNameFromPayloadKey(payloadKey);
  }
}

templates.application\.hbs

<h1>Foos</h1>
<ul>
	{{#each this.model as |foo|}}
		<li>{{foo.name}}</li>
	{{/each}}
</ul>

twiddle\.json

{
  "version": "0.17.1",
  "EmberENV": {
	  "LOG_VERSION": false,
    "EXTEND_PROTOTYPES": false,
    "FEATURES": {}
  },
  "options": {
    "use_pods": false,
    "enable-testing": false
  },
  "dependencies": {
    "ember": "3.18.1",
    "ember-template-compiler": "3.18.1",
    "ember-testing": "3.18.1",
    "pretender": "https://unpkg.com/[email protected]/dist/pretender.bundle.js"
  },
  "addons": {
    "@glimmer/component": "1.0.0",
    "ember-data": "3.18.0"
  }
}