Start the light probe only when entering ar-mode, update the VR envir…

…onment only when a light probe was set up in the first place

src/components/scene/reflection.js

@@ -42,11 +42,10 @@ module.exports.Component = register('reflection', {
     }
 
     this.el.addEventListener('enter-vr', function () {
+      if (!self.el.is('ar-mode')) { return; }
       var renderer = self.el.renderer;
       var session = renderer.xr.getSession();
-      if (
-        session.requestLightProbe && self.el.is('ar-mode')
-      ) {
+      if (session.requestLightProbe) {
         self.startLightProbe();
       }
     });
@@ -61,9 +60,9 @@ module.exports.Component = register('reflection', {
     this.xrLightProbe = null;
     if (this.probeLight) {
       this.probeLight.components.light.light.intensity = 0;
+      this.needsVREnvironmentUpdate = true;
+      this.el.object3D.environment = this.cubeRenderTarget.texture;
     }
-    this.needsVREnvironmentUpdate = true;
-    this.el.object3D.environment = this.cubeRenderTarget.texture;
   },
   startLightProbe: function () {
     this.needsLightProbeUpdate = true;