Is this a bug in Flash's E4X parsing?

Had to narrow down why someone else's AIR app wasn't loading anything today, and discovered a (BUG?) quirk with this code:

 public static function getScreenDataByID(id:String="",dispose:Boolean = true) : ScreenVO {
        var xml:XML = assets.getXml("app-data");
        var screen:XMLList = new XMLList(xml.screen.(@id == id));
        trace('screen=', screen);
        return screen.data;

    }

//output: screen=

After a lot of head banging I changed it to this:

 public static function getScreenDataByID(id:String="",dispose:Boolean = true) : ScreenVO {
         var xml:XML = assets.getXml("app-data");
         var newId:String = id.toString();
         var screen:XMLList = new XMLList(xml.screen.(@id == newId));
         trace('screen=', screen);
         return screen.data;

    }
  //output: screen=**correct data from xml***

Is this a bug in Flash?

I have never come across anything like this.

• 
  

  Just to clarify, the id being passed to the function was a String like 'home' and was of type String already.

  
  


• 
  

  and the assets.getXml function returned the correct xml in both cases.