AVPlayerViewController 从画中画应用程序崩溃回到全屏模式

Question

当我们从 PIP 模式返回全屏模式时，视频继续全屏播放，但当我点击暂停按钮时，应用程序崩溃了。谁能告诉我为什么会这样？

func playerViewControllerDidStopPictureInPicture(_ playerViewController: AVPlayerViewController) {
        guard let player = self.moviePlayer?.player else {
            return
        }
    }


func playerViewController(_ playerViewController: AVPlayerViewController, restoreUserInterfaceForPictureInPictureStopWithCompletionHandler completionHandler: @escaping (Bool) -> Void) {
        let currentviewController = navigationController?.visibleViewController
        if currentviewController != playerViewController{
            currentviewController?.present(playerViewController, animated: true, completion: nil)
        }else {
            present(playerViewController, animated: false)
        }
    }