BitmapData#draw() bug?

/**
 * Copyright codeonwort ( http://wonderfl.net/user/codeonwort )
 * MIT License ( http://www.opensource.org/licenses/mit-license.php )
 * Downloaded from: http://wonderfl.net/c/7b2l
 */

package {
    import flash.text.TextField;
    
    import flash.display.Sprite;
    import flash.display.BitmapData;
    import flash.geom.Matrix;
    import flash.geom.ColorTransform;
    import flash.display.Bitmap;
    
    public class BitmapData_Draw_Bug extends Sprite {
        public function BitmapData_Draw_Bug() {
            // write as3 code here..
            var mc:Sprite = new Sprite
            mc.graphics.lineStyle(1, 0x0)
            mc.graphics.drawRect(0, 0, 300, 200)
            mc.graphics.lineStyle()
            mc.graphics.beginFill(0xff0000)
            mc.graphics.drawCircle(150, 100, 50)
            
            var bd:BitmapData = new BitmapData(mc.width+.5, mc.height+.5, true, 0x0)
            bd.draw(mc)
            addChild(new Bitmap(bd)).y = bd.height
            
            var bd_wanted:BitmapData = bd.clone()
            var temp:BitmapData = bd_wanted.clone()
            addChild(new Bitmap(bd_wanted))
            
            var m:Matrix = new Matrix
            m.translate(-bd.width*.5, -bd.height*.5)
            m.scale(1.2, 1.2)
            m.translate(bd.width*.5, bd.height*.5)
            
            
            bd.draw(bd, m, new ColorTransform(1,1,1, .5)) // here
            
            bd_wanted.draw(temp)
            bd_wanted.draw(temp, m, new ColorTransform(1,1,1,.5))
            with(TextField(addChild(new TextField))){
                autoSize = 'left'
                text = 'What I wanted'
            }
        }
    }
}