Cube Camera Reflection Bug

Cube Camera Reflection Bug

HTML

<script src="https://threejs.org/build/three.min.js"></script>
<script src="https://threejs.org/examples/js/controls/OrbitControls.js"></script>

JavaScript

// a basic three.js scene

var container, renderer, scene, camera, cubeCamera, floor, controls;

init();
animate();

function init() {

    // renderer
    renderer = new THREE.WebGLRenderer({
        antialias: false
    });
    renderer.setSize(window.innerWidth, window.innerHeight);
    renderer.setClearColor(0xccccff);
    container = document.createElement('div');
    document.body.appendChild(container);
    container.appendChild(renderer.domElement);

    // scene
    scene = new THREE.Scene();
    scene.add(new THREE.AmbientLight(0xFFFFFF));

    // camera
    camera = new THREE.PerspectiveCamera(45, window.innerWidth / window.innerHeight, 1, 10000);
    camera.position.set(0, 10, 10);
    camera.lookAt(scene.position);

    // (camera) controls
    // mouse controls: left button to rotate, 
    //    mouse wheel to zoom, right button to pan
    controls = new THREE.OrbitControls(camera, renderer.domElement);

    var cubeRenderTarget = new THREE.WebGLCubeRenderTarget( 512, { format: THREE.RGBFormat, generateMipmaps: true, minFilter: THREE.LinearMipmapLinearFilter } );

    cubeCamera = new THREE.CubeCamera( 0.1, 5000, cubeRenderTarget );
    scene.add( cubeCamera );

		var loader = new THREE.TextureLoader();
    loader.crossOrigin = "anonymous"

    var sphere = new THREE.Mesh( new THREE.SphereGeometry( 2, 32, 32 ), new THREE.MeshBasicMaterial( { map: loader.load( "https://i.imgur.com/Ip19PQt.jpg" ) } ) );
    sphere.position.set(0, +2, 0);
		scene.add(sphere);


		var floorMaterial = /*new THREE.MeshBasicMaterial( { envMap: cubeRenderTarget.texture, side:THREE.DoubleSide, reflectivity: 0.5 } )*/ new THREE.MeshPhongMaterial( { envMap: cubeRenderTarget.texture, side:THREE.DoubleSide, reflectivity: 0.5 } );
	  var floorGeometry = new THREE.PlaneGeometry(10, 10);
	  floor = new THREE.Mesh(floorGeometry, floorMaterial);
    floor.rotation.x = Math.PI / 2;
	  scene.add(floor);
    
    // events
    window.addEventListener('resize', onWindowResize,...