Outputvolume of AVAudioSession returning rounded values

Using the hardware volume buttons on the iPhone, you have 16 steps you can adjust your volume to. I want to implement a volume control slider in my app. I am updating the value of the slider using AVAudioSession.sharedInstance().outputVolume. The problem is that this returns values rounded to the nearest 0 or 5. This makes the slider jump around. .formatted() is not causing this problem. You can recreate the problem using code below.

@main
struct VolumeTestApp: App {
    init() {
        try? AVAudioSession.sharedInstance().setActive(true)
    }
    var body: some Scene {
        WindowGroup {
            ContentView()
        }
    }
}

struct ContentView: View {
    @State private var volume = Double()
    @State private var difference = Double()
    var body: some View {
        VStack {
            Text("The volume changed by \(difference.formatted())")
            Slider(value: $volume, in: 0...1)
        }
        .onReceive(AVAudioSession.sharedInstance().publisher(for: \.outputVolume), perform: { value in
            volume = Double(value)
        })
        .onChange(of: volume) { oldValue, newValue in // Only used to make the problem more obvious
            if oldValue > newValue {
                difference = oldValue - newValue
            } else {
                difference = newValue - oldValue
            }
        }
    }
}

Here is a video of the problem in action: https://share.icloud.com/photos/00fmp7Vq1AkRetxcIP5EXeAZA

What am I doing wrong or what can I do to avoid this?

Thank you