I've encountered this bug while working on my game.
When you have more than 1 Layer and a Sprite assigned with the ScrollTo Behavior it won't zoom in on the object but instead zoom to the center of the canvas :(
Here is a .capx demonstrating the problem.
If you delete the GUI-layer it will work as it should.
http://dl.dropbox.com/u/45711709/LayerScaleScrollToBug.capx