Camera positionCartographic not always updated in 2D?

[mramato]

Run this code. In 2D mode, zooming in doesn't trigger the console message, you have to move the camera after zooming to get it to happen.

var viewer = new Cesium.Viewer('cesiumContainer');
var scene = viewer.scene;

var lastHeight;
scene.preRender.addEventListener(function(){
    var camera = scene.camera;
    var height = camera.positionCartographic.height;
    if(lastHeight !== height) {
        //Camera height has changed
        console.log('New height: ' + height);
        lastHeight = height;
    }
});