Cube Shader problem

HTML

<script src="https://cdnjs.cloudflare.com/ajax/libs/stats.js/r16/Stats.min.js"></script>
<div id="stats"></div>

CSS

body {
  background-color: #000;
  margin: 0px;
  overflow: hidden;
}

JavaScript

import * as THREE from 'https://cdn.jsdelivr.net/npm/three@0.121.1/build/three.module.js';
import { OrbitControls } from 'https://cdn.jsdelivr.net/npm/three@0.121.1/examples/jsm/controls/OrbitControls.js';
import Stats from 'https://cdn.jsdelivr.net/npm/three@0.121.1/examples/jsm/libs/stats.module.js';

var renderer, scene, camera, controls, container, stats;

init();
animate();

function init() {

  stats = new Stats();
  container = document.getElementById('stats');
  container.appendChild(stats.domElement);
  
  console.log(THREE.REVISION);

  renderer = new THREE.WebGLRenderer({ antialias: true });
  renderer.setSize(window.innerWidth, window.innerHeight);
  document.body.appendChild(renderer.domElement);

  scene = new THREE.Scene();

  camera = new THREE.PerspectiveCamera(40, window.innerWidth / window.innerHeight, 10, 100000);
  camera.position.set(-400, 200, 400);

  controls = new OrbitControls(camera, renderer.domElement);

  scene.add(new THREE.HemisphereLight(0xffffff, 0x080808, 1));
	
	var loader = new THREE.CubeTextureLoader();
	loader.setPath( 'https://threejs.org/examples/textures/cube/Park3Med/' );
	var envMap = loader.load(['px.jpg', 'nx.jpg', 'py.jpg', 'ny.jpg', 'pz.jpg', 'nz.jpg']);


  let objectMaterial = new THREE.MeshStandardMaterial( { envMap: envMap } );
  scene.add(new THREE.Mesh(new THREE.CubeGeometry(50, 50, 50), objectMaterial));
  
  let roomShader = THREE.ShaderLib.cube;
  let roomMaterial = new THREE.ShaderMaterial( {
    fragmentShader: roomShader.fragmentShader,
    vertexShader: roomShader.vertexShader,
    uniforms: THREE.UniformsUtils.clone( roomShader.uniforms ),
    depthWrite: false,
    depthTest: false,
    fog: false,
    side: THREE.BackSide
  });
	
	Object.defineProperty( roomMaterial, 'envMap', {

		get: function () {

			return this.uniforms.envMap.value;

		}

	} );
	
	roomMaterial.uniforms.envMap.value = envMap;
  
  let roomGeometry = new THREE.BoxBufferGeometry(50000, 50000, 50000);
  let room = new...