UserAgent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/59.0.3048.0 Safari/537.36

Steps to reproduce the problem:
var testRect:Rectangle = new Rectangle(1,2,3,4);
				ExternalInterface.call('console.log', "testRect (" + testRect.x + ", " + testRect.y + ", " + testRect.width + ", " + testRect.height + ")\n");

				var clonedRect:Rectangle = ObjectUtil.clone(testRect) as Rectangle;
				ExternalInterface.call('console.log', "clonedRect (" + clonedRect.x + ", " + clonedRect.y + ", " + clonedRect.width + ", " + clonedRect.height + ")\n");

				var buffer:ByteArray = new ByteArray();
				buffer.writeObject(clonedRect);
				buffer.position = 0;
				var clonedRect2:Rectangle = buffer.readObject() as Rectangle;

				ExternalInterface.call('console.log',"clonedRect2 (" + clonedRect2.x + ", " + clonedRect2.y + ", " + clonedRect2.width + ", " + clonedRect2.height + ")\n");

What is the expected behavior?
console:

testRect (1, 2, 3, 4)
clonedRect (1, 2, 3, 4)
clonedRect2 (1, 2, 3, 4)

What went wrong?
console:

testRect (1, 2, 3, 4)
clonedRect (1, 2, 3, 6)
clonedRect2 (1, 2, 3, 8)

Cloning writing/reading object Rectangle is always adding y to height!

Did this work before? No 

Chrome version: 59.0.3048.0  Channel: canary
OS Version: 10.0
Flash Version: Shockwave Flash 25.0 r0

On Chrome 57.0.2987.110 x32 works fine...
Also installing flashplayer works fine, only ppapi x64 gives this error.