Why MapKit Is So Unpredictable for macOS?

I have an existing iOS app with MapKit. It always shows the current user location with UserAnnotation. But the same isn't true for macOS. I have this sample macOS application in SwiftUI. In the following, the current user location with a large blue dot appears only occasionally. It won't, 19 of 20 times. Why is that? I do have a location privacy key in Info.plist. And the Location checkbox is on under Signing & Capabilities.

import SwiftUI
import MapKit

struct ContentView: View {
    @State private var markerItems: [MarkerItem] = [
        MarkerItem(name: "Farmers Market 1", lat: 35.681, lon: 139.691),
        MarkerItem(name: "Farmers Market 2", lat: 35.685, lon: 139.695),
        MarkerItem(name: "Farmers Market 3", lat: 35.689, lon: 139.699)
    ]
    @State private var position: MapCameraPosition = .automatic

    var body: some View {
        Map(position: $position) {
            UserAnnotation()
            
            ForEach(markerItems, id: \.self) { item in
                Marker(item.name, coordinate: CLLocationCoordinate2D(latitude: item.lat, longitude: item.lon))
            }
        }
        .mapControlVisibility(.hidden)
        .mapStyle(.standard(elevation: .realistic))
        .ignoresSafeArea()
    }
}

#Preview {
    ContentView()
}

struct MarkerItem: Hashable {
    let name: String
    let lat: Double
    let lon: Double
}