Question about alpha fading (fast)

Is there a way to avoid the problem demonstrated here:

http://cid-151851e0a027f0bd.skydrive.live.com/self.aspx/.Public/testalpha.swf

Where if you have an MC with children MC that are on-top of eachother you get an inconsistent fade? I don’t seem to remember this happening in earlier versions of flash.

This is all the code:

import gs.TweenLite;

TweenLite.to(testbox, 3, {alpha: 0});