Starling - BlurFilter Goes White - Probably A Bug

Question

I have a strange situation about BlurFilter and ColorMatrixFilter with Starling Framwork.

In my senario, there are two sprites "A" and "B". "B" is child of "A".

.

In the begining, "A" had only BlurFilter and it was working as expected.

But when I add a ColorMatrixFilter to "B", "B" is working but "A" turned white.

Do you know where is my mistake or is it a bug ?

EDIT: Sprite A is GameArea, Sprite B is LeafDustEffect

var cmf:ColorMatrixFilter = new ColorMatrixFilter();                
cmf.adjustBrightness(-0.55);
leafDustEffect.filter = cmf;                
gameArea.addChild(leafDustEffect);

gameArea.filter = new BlurFilter(0, 0);
Starling.juggler.tween(gameArea.filter, 0.5, { blurX: 2.0, blurY: 2.0 });

EDIT 2: I Found That, Adding ColorMatrix Object Inside BlurFiltered Object Coused That Issue.