IconMenuItem only accepts Drawable icon, not BitmapResource/BitmapType, contrary to documentation

SDK: 4.1.5

Device: Fenix 7 in simulator

References:

https://forums.garmin.com/developer/connect-iq/f/discussion/306285/menu2-a-lot-of-questions/1482231#1482231
|https://forums.garmin.com/developer/connect-iq/f/discussion/306285/menu2-a-lot-of-questions/1482431#1482431
https://forums.garmin.com/developer/connect-iq/f/discussion/306285/menu2-a-lot-of-questions/1482431#1482431

Code that doesn't work:

var menu = new WatchUi.Menu2({:title => "Wind Surf"});
var appIcon = WatchUi.loadResource(Rez.Drawables.LauncherIcon);

menu.addItem(new WatchUi.IconMenuItem("Sails", null, "item_sail", appIcon, null));

Error: Unhandled Exception
Exception: UnexpectedTypeException: Unexpected icon type, expected Drawable

Code that works:

       //...
        menu.addItem(
            new WatchUi.IconMenuItem(
                "Sails",
                null,
                "item_sail",
                new CustomIcon(Rez.Drawables.LauncherIcon),
                null
            )
        );
        // ...
    } // end of function
    // ...
} // end of class

class CustomIcon extends WatchUi.Drawable {
    var bitmapResource = null;
    public function initialize(resourceId) {
        Drawable.initialize({});
        bitmapResource = WatchUi.loadResource(resourceId);
    }

    public function draw(dc as Dc) as Void {
        dc.setColor(Graphics.COLOR_TRANSPARENT, Graphics.COLOR_TRANSPARENT);
        dc.clear();
        dc.drawBitmap(0, 0, bitmapResource);
    }
}

Documentation:

https://developer.garmin.com/connect-iq/api-docs/Toybox/WatchUi/IconMenuItem.html#initialize-instance_function

initialize(label as Lang.String, subLabel as Lang.String or Null, identifier, icon as Graphics.BitmapType or WatchUi.Drawable, options as { :alignment as MenuItem.Alignment } or Null)