Transition with a bounce easer acting on top/left constraint values doesn't bounce

Steps to reproduce:
1. Compile and run this application:

<s:WindowedApplication xmlns:fx="http://ns.adobe.com/mxml/2009"
xmlns:s="library://ns.adobe.com/flex/spark">

<s:states>
<s:State name="aState"/>
<s:State name="bState"/>
</s:states>

<s:transitions>
<s:Transition>
<s:Move targets="

" duration="3000">
<s:easer>
<s:Bounce />
</s:easer>
</s:Move>
</s:Transition>
</s:transitions>

<s:Button id="btn" click="this.currentState = (this.currentState == 'aState')?'bState':'aState';"
top.aState="10" left.aState="10" top.bState="300" left.bState="300"/>

</s:WindowedApplication>

2. Click the button
3.

Actual Results:

The button moves with what appears to be a linear ease

Expected Results:

The button should move with a bounce ease

Workaround (if any):

Use x/y to position the Button instead of top/left