BabylonJS - toEulerAngles BUG

http://www.html5gamedevs.com/topic/3159-quaternionrotationyawpitchroll-parameters-and-toeulerangles-result-should-be-the-same/

HTML

<script src="https://rawgithub.com/BabylonJS/Babylon.js/v1.8.0/babylon.1.8.0.js"></script>
<div id="rootDiv">
  <canvas id="renderCanvas"></canvas>
  <canvas id="canvas_2D"></canvas>
</div>

CSS

html, body, div, canvas {
    width: 100%;
    height: 100%;
    padding: 0;
    margin: 0;
    overflow: hidden;
}

#canvas_2D {
    position: absolute;   
    top: 0;
    pointer-events: none;
}

JavaScript

var rotation = new BABYLON.Vector3(0.78, 0.78, 0.78);

var q = BABYLON.Quaternion.RotationYawPitchRoll(0, 0, 1000);
var eulerAngles = q.toEulerAngles();


var drawAxisFor = [];

// Get the Canvas element from our HTML below
var canvas = document.getElementById("renderCanvas");
// Load BABYLON 3D engine
var engine = new BABYLON.Engine(canvas, true);

var scene = new BABYLON.Scene(engine);

// Create a camera
var camera = new BABYLON.ArcRotateCamera ("Camera",  -1.6, 1.1, 140, BABYLON.Vector3.Zero(), scene);

// Attach the camera to the scene
scene.activeCamera.attachControl(canvas);

// Create meshes
var ground = new BABYLON.Mesh.CreatePlane("ground", 100, scene);
ground.rotation.x = Math.PI / 2;

var model1 = BABYLON.Mesh.CreateBox("model1", 7, scene);
model1.position.x = -30;
model1.rotation = rotation;

var model2 = BABYLON.Mesh.CreateBox("model2", 7, scene);
model2.position.x = 30;
model2.rotation = eulerAngles;

var material = new BABYLON.StandardMaterial("default", scene);
material.emissiveColor = new BABYLON.Color3(0.3, 0.3, 0.5);
material.wireframe = true;

ground.material = material;
model1.material = material;
model2.material = material;

drawAxisFor.push(model1);
drawAxisFor.push(model2);

var canvas2D = document.getElementById("canvas_2D");
var context2D = canvas2D.getContext("2d");

//Add a placeholder function for browsers that don't have setLineDash()
if (!context2D.setLineDash) {
    context.setLineDash = function () {}
}

var clearCanvas2D = function(){
    canvas2D.width = window.innerWidth;
    canvas2D.height = window.innerHeight;
};

var drawAxis = function(camera, mesh, drawAncestors, pivot){			
   
    context2D.lineWidth = 1;
    context2D.shadowColor = '#000000';
    context2D.lineCap = "square";
    context2D.shadowBlur = 10;
    context2D.shadowOffsetX = 0;
    context2D.shadowOffsetY = 0;

    //////////////////////// update camera view matrix
    var viewMatrix = camera.getViewMatrix();
    //////////////////////////
    
    var...