使用UIViewPropertyAnimator沿弯曲路径驱动动画？

Question

I have an interruptible transition that is driven by UIViewPropertyAnimator and I would like to animate a view along a non linear path to its destination.

Doing some research I've found that the way to do this is by using: CAKeyframeAnimation . However, I'm having issue coordinating the animations also I'm having issue with the CAKeyframeAnimation fill mode. It appears to be reverse even though I've set it to forwards.

Below is the bezier path:

let bezierPath = self.generateCurve(from: CGPoint(x: self.itemStartFrame.midX, y: self.itemStartFrame.midY), to: CGPoint(x: self.itemEndFrame.midX, y: self.itemEndFrame.midY), bendFactor: 1, thickness: 1)

func generateCurve(from: CGPoint, to: CGPoint, bendFactor: CGFloat, thickness: CGFloat) -> UIBezierPath {

    let center = CGPoint(x: (from.x+to.x)*0.5, y: (from.y+to.y)*0.5)
    let normal = CGPoint(x: -(from.y-to.y), y: (from.x-to.x))
    let normalNormalized: CGPoint = {
        let normalSize = sqrt(normal.x*normal.x + normal.y*normal.y)
        guard normalSize > 0.0 else { return .zero }
        return CGPoint(x: normal.x/normalSize, y: normal.y/normalSize)
    }()

    let path = UIBezierPath()

    path.move(to: from)

    let midControlPoint: CGPoint = CGPoint(x: center.x + normal.x*bendFactor, y: center.y + normal.y*bendFactor)
    let closeControlPoint: CGPoint = CGPoint(x: midControlPoint.x + normalNormalized.x*thickness*0.5, y: midControlPoint.y + normalNormalized.y*thickness*0.5)
    let farControlPoint: CGPoint = CGPoint(x: midControlPoint.x - normalNormalized.x*thickness*0.5, y: midControlPoint.y - normalNormalized.y*thickness*0.5)


    path.addQuadCurve(to: to, controlPoint: closeControlPoint)
    path.addQuadCurve(to: from, controlPoint: farControlPoint)
    path.close()
    return path
}

Path visualization:

let shapeLayer = CAShapeLayer()
shapeLayer.path = bezierPath.cgPath
shapeLayer.strokeColor = UIColor.red.cgColor
shapeLayer.lineWidth = 2
containerView.layer.addSublayer(shapeLayer)

Here's the CAKeyframeAnimation that resides inside of the UIViewPropertyAnimator

let curvedPathAnimation = CAKeyframeAnimation(keyPath: "position")
curvedPathAnimation.path = bezierPath.cgPath
curvedPathAnimation.fillMode = kCAFillModeForwards
curvedPathAnimation.calculationMode = kCAAnimationPaced
curvedPathAnimation.duration = animationDuration
self.attatchmentView.layer.add(curvedPathAnimation, forKey: nil)

So far this animation along the correct path, however the animation reverse back to it's starting position and is not in sync with the property animator.

Any suggestions?