MPMediaPlayback.currentPlaybackRate no longer working in iOS 15.4?

Just wondering if anyone else is having issues with currentPlaybackRate in release version of iOS 15.4? In my particular case this is using MPMusicPlayerController.applicationQueuePlayer.

I've always had issues controlling this property reliably but from what I can see it is now completely non-operational in 15.4.

I've isolated this behavior in a trivial project, and will file a radar, but hoping others may have some insight first.

FWIW- This is my trivial test case:

class ViewController: UIViewController {
    lazy var player: MPMusicPlayerApplicationController = {
        let player = MPMusicPlayerController.applicationQueuePlayer
        player.repeatMode = .none
        player.shuffleMode = .off
        player.beginGeneratingPlaybackNotifications()
        return player
    }()

    override func viewDidLoad() {
        super.viewDidLoad()

        NotificationCenter.default.addObserver(forName: .MPMusicPlayerControllerPlaybackStateDidChange, object: nil, queue: .main) { [weak self] notification in
            guard let notificationPlayer = notification.object as? MPMusicPlayerApplicationController,
                  notificationPlayer === self?.player else {
                return
            }
            
            debugPrint("Player state now: \(notificationPlayer.playbackState)")
        }
    }

    @IBAction func goAction(_ sender: Any) {
        guard let item = MPMediaQuery.songs().items?.randomElement() else {
            debugPrint("Unable to access media items")
            return
        }

        debugPrint("Now playing item: \(item.title ?? "")")
        player.setQueue(with: [item.playbackStoreID])

        player.prepareToPlay() { error in
            guard error == nil else {
                debugPrint("Player error: \(error!.localizedDescription)")
                return
            }

            DispatchQueue.main.async { [weak self] in
                self?.player.play()
            }
        }
    }

    @IBAction func slowAction(_ sender: Any) {
        debugPrint("Setting currentPlaybackRate to 0.5")
        player.currentPlaybackRate = 0.5
        checkPlaybackRate()
    }

    @IBAction func fastAction(_ sender: Any) {
        debugPrint("Setting currentPlaybackRate to 1.5")
        player.currentPlaybackRate = 1.5
        checkPlaybackRate()
    }

    func checkPlaybackRate(afterSeconds delay: TimeInterval = 1.0) {
        DispatchQueue.main.asyncAfter(deadline: .now() + delay) {
            debugPrint("After \(delay) seconds currentPlaybackRate now: \(self.player.currentPlaybackRate)")
        }
    }
}

Typical console output:

"Now playing item: I Know You Know"
"Player state now: MPMusicPlaybackState(rawValue: 2)"
"Player state now: MPMusicPlaybackState(rawValue: 1)"
"Setting currentPlaybackRate to 1.5"
"After 1.0 seconds currentPlaybackRate now: 1.0"
"Setting currentPlaybackRate to 0.5"
"After 1.0 seconds currentPlaybackRate now: 1.0"