Ember Data Validation Errors Clearing on Edit

adapters.my-model.js

import DS from 'ember-data';
import RSVP from 'rsvp';

export default DS.Adapter.extend({
	createRecord(store, type, snapshot) {
    return RSVP.reject(new DS.InvalidError([{
      title: 'my_property',
      detail: 'invalid_string',
      source: { pointer: '/data/attributes/my_property' }
    }]));
  }
});

controllers.application.js

import Ember from 'ember';

export default Ember.Controller.extend({
  appName: 'Ember Twiddle',
  
  model: null,
  
  actions: {
  	saveModel() {
      if (!this.get('model')) {
        this.set('model', this.store.createRecord('my-model', {}));
      }
      this.get('model').save();
    }
  }
});

models.my-model.js

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

export default Model.extend({
  my_property: attr('string')
});

templates.application.hbs

<h1>Welcome to {{appName}}</h1>
<br>
<br>
{{outlet}}
<br>
<br>

<p>1. Press Save Model</p>
<p>2. Edit the field</p>
<p>3. Validation errors disappear</p>

{{input value=model.my_property}}

<p>Validation errors:</p>
{{#each model.errors as |error|}}
	<p>{{error.message}}</p>
{{/each}}

<button onclick={{action 'saveModel'}}>Save Model</button>

twiddle.json

{
  "version": "0.14.1",
  "EmberENV": {
    "FEATURES": {}
  },
  "options": {
    "use_pods": false,
    "enable-testing": false
  },
  "dependencies": {
    "jquery": "https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.js",
    "ember": "2.18.2",
    "ember-template-compiler": "2.18.2",
    "ember-testing": "2.18.2"
  },
  "addons": {
    "ember-data": "2.18.2"
  }
}