Bug: ember-cli-mirage factory is ignored if model is created by pluarlized name

mirage.factories.post.js

import { Factory } from 'ember-cli-mirage';
import { isEmpty } from '@ember/utils';

export default Factory.extend({
  title: 'an example post'
});

mirage.scenarios.default.js

export default function(server) {
  let singular = server.create('post', 1);
  let plural = server.create('posts', 1);
  console.log('singular', singular.title, singular);
  console.log('plural', plural.title, plural);
}

templates.application.hbs

<h1>Bug: ember-cli-mirage factory is ignored if model is created by pluarlized name</h1>
<p>
  Code triggering the bug lives in <i>mirage/scenarios/default.js</i>. Please open up your developer console. You will see that the <i>title</i> property for the record created by pluralized model is <i>undefined</i>. Except for that the model is created just fine. Bug seems to only affect factories.
</p>

twiddle.json

{
  "version": "0.15.0",
  "ENV": {
    "ember-cli-mirage": {
    	"enabled": true
		}
	},
  "EmberENV": {
    "FEATURES": {}
  },
  "options": {
    "use_pods": false,
    "enable-testing": false
  },
  "dependencies": {
    "jquery": "https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.js",
    "ember": "3.2.2",
    "ember-template-compiler": "3.2.2",
    "ember-testing": "3.2.2"
  },
  "addons": {
    "ember-data": "3.2.0",
    "ember-cli-mirage": "0.4.7"
  }
}