UIscrollView, Autolayout and UIDynamicAnimator - Views flash

Question

I have a scrollView with two views in it. I want them to have gravity attached to them

    animator = UIDynamicAnimator(referenceView: scrollView)
    createViews()
    var gravity : UIGravityBehavior = UIGravityBehavior(items: [view])
    animator.addBehavior(gravity)

The views are created and added with autolayout.

        var view = UIView()
        scrollView.addSubview(view)
        view.setTranslatesAutoresizingMaskIntoConstraints(false)
        self.view.addConstraints(NSLayoutConstraint.constraintsWithVisualFormat("|-(\(xPostion))-[view(50)]", options:NSLayoutFormatOptions(0), metrics:nil, views:["view":view]))
        self.view.addConstraints(NSLayoutConstraint.constraintsWithVisualFormat("V:[view(50)]-(\(yPostion))-|", options:NSLayoutFormatOptions(0), metrics:nil, views:["view":view]))

I can get the gravity to work just fine but when I scroll the views reset to the original position and then flash back to where they should be.

Below the two views are falling, when I pull on the scrollView you can see them flash back to there start position for a second.

Edit: as far as i can tell this has to do with autolayout and the scrollview. If I use frames it was fine.