Resize and onSizeChange fires many times + example code

[BdR]

I'm working on a game and I'm trying to implement dynamic resizing, but I have some unexplained issues. My game is optimized for a phone portrait layout. Depending on the phone screen size (or browser window size) it should adjust the layout, the width is fixed size but the height is adjusted. So make it taller if necessary and center some sprites or texts.

I've created a code example which works, but the resize function gets called many times. So to isolate and test the resize function see this github example:
https://github.com/BdR76/phaserresize/

The code example has 4 states: Boot, Preloader, MainMenu, Game. I won't post all the code here, but what I've done is essentially this:

// Boot state, in create() setup the scale.setResizeCallback event handler.
mygame.Bootup.prototype = {
	create: function(){
		this.game.scale.setResizeCallback(this.resizeCallback, this);
		this.game.scale.onSizeChange.add(this.onSizeChange, this);
	},

	resizeCallback: function(manager) {
		// browser window changes size, resize the game
		var ratio = window.innerHeight / window.innerWidth;
		if (GAME_WIDTH * ratio > GAME_HEIGHT) {
			this.scale.setGameSize(GAME_WIDTH, Math.floor(GAME_WIDTH * ratio)) // too tall, adjust height resolution
		} else {
			this.scale.setGameSize(GAME_WIDTH, GAME_HEIGHT); // too wide, just use fixed width and empty side bars
		};
	},

	onSizeChange: function() {
		// fire the game resize event for the current state (make sure each state has this)
		this.game.state.callbackContext.resize();
	}
};

And then both the MainMenu and Game have a resize function that adjusts its layout and positions of sprites, text etc., it's a little similar to this topic. My github code example works, however the resizeCallback function from the Bootup state gets called all the time. It fires many times right from the beginning even before I do anything. I'm not resizing and not switching state or anything, and it get called not once but continually.

So my questions is: Why is the onSizeChange event called so often? 

Is this normal and should I use a different event?

[BdR]

Btw I did some searching and the many calls to onSizeChange may be related to this older issue:
https://github.com/photonstorm/phaser/issues/1400