strange-else-problem

controllers.application.js

import Controller from '@ember/controller';
import { equal, gt } from '@ember/object/computed';

export default Controller.extend({
  init() {
    this._super(...arguments);
    
    this.cars = [];
    this.set('counter', 0);
  },
  
  isNotReady: equal('counter', 0),
  
  isReady: equal('counter', 1),
  
  actions: {
    makeReady() {
      let { counter } = this;
			this.set('counter', counter + 1);
      console.log('counter before:', counter, '; counter after:', counter + 1);
    }
  }
});

templates.application.hbs

{{#each cars as |car|}}
  <p>Car!</p>
{{else}}
	<p>
  {{#if isNotReady}}
    I'm not ready
  {{else if isReady}}
    I'm ready
  {{else}}
  	I'm beyond ready
  {{/if}}
  </p>
{{/each}}

<button {{action "makeReady"}} type="button">
	Click to make ready
</button>

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": "3.4.2"
  }
}