CLONE -ColumnSet breaks ColumnSeries labels

This is broken again in 4.1. Works in 4.0.

Here's a simple example:

<?xml version="1.0" encoding="utf-8"?>
<s:Application xmlns:fx="http://ns.adobe.com/mxml/2009"
xmlns:s="library://ns.adobe.com/flex/spark"
xmlns:mx="library://ns.adobe.com/flex/mx">
<mx:ColumnChart>
<mx:series>
<mx:ColumnSet>
<mx:series>
<mx:ColumnSeries xField="x" yField="y" labelPosition="outside"/>
</mx:series>
</mx:ColumnSet>
</mx:series>
<mx:dataProvider>
<fx:Array>
<fx:Object x="1" y="1"/>
<fx:Object x="2" y="2"/>
<fx:Object x="3" y="3"/>
</fx:Array>
</mx:dataProvider>
</mx:ColumnChart>
</s:Application>

Workaround:
Add the ColumnSeries to the ColumnSet in actionscript. See the attached project.