Este é o meu método de animação (PreloaderView.swift)

public func performAction(action: PreloaderAction)
{
    let highOpacity = CABasicAnimation.init(keyPath: "opacity")
    let middleOpacity = CABasicAnimation.init(keyPath: "opacity")
    let lowOpacity = CABasicAnimation.init(keyPath: "opacity")

    if action == .PreloaderActionNone {
        self.thirdShape.removeAllAnimations()
        self.firstShape.opacity = 0.3;
        self.secondShape.opacity = 0.5
        self.thirdShape.opacity = 1.0
    } else if action == .PreloaderActionFailure {
        UIView.animateWithDuration(2, animations: {
            self.thirdShape.strokeColor = UIColor.redColor().CGColor
        }) {(completed : Bool) in
            self.thirdShape.strokeColor = self.ringColor.CGColor
        }

    }

    if action == .PreloaderActionStart {

        highOpacity.fromValue = 0.0
        highOpacity.toValue = 1.0
        highOpacity.duration = animationDuration
        highOpacity.autoreverses = true
        highOpacity.repeatCount = .infinity
        self.secondShape.addAnimation(highOpacity, forKey: "highOpacity")

        middleOpacity.fromValue = 0.0
        middleOpacity.toValue = 1.0
        middleOpacity.duration = animationDuration
        middleOpacity.autoreverses = true
        middleOpacity.repeatCount = .infinity
        middleOpacity.beginTime = CACurrentMediaTime() + 0.33
        self.firstShape.addAnimation(middleOpacity, forKey: "middleOpacity")

        lowOpacity.fromValue = 0.0
        lowOpacity.toValue = 1.0
        lowOpacity.duration = animationDuration
        lowOpacity.autoreverses = true
        lowOpacity.beginTime = CACurrentMediaTime() + 0.66
        lowOpacity.repeatCount = .infinity
        self.thirdShape.addAnimation(lowOpacity, forKey: "lowOpacity")

    }
}

Este é o meu arquivo de recreio

e playground no navegador do projeto

As animações funcionam bem no dispositivo, mas quando uso animações de playground, elas não funcionam.