Possible MacOS SwiftUI onFocusChange bug

I think I've found a bug with focusable(_: onFocusChange:) on MacOS with SwiftUI and wanted to sanity check it here before using feedback assistant. This is with Xcode 11.3.1

When I create the window, the VStack inside thinks it is in focus. But the onFocusChange closure never gets called to say it loses focus. As a result, both my VStacks in both my windows think they are infocus.

Demonstration project at https://github.com/darrellroot/focusBug/

Here's my ContentView which displays whether it thinks it is in focus:

struct ContentView: View {
    @State var inFocus = false
    let windowCount: Int
    var body: some View {
        VStack {
            Text("Focus Window \(windowCount)")
            inFocus ? Text("This window thinks it is in focus") : Text("This window does not think it is in focus")
        }.padding(50).focusable() { newFocus in
            debugPrint("onFocusChange: \(newFocus)")
            self.inFocus = newFocus
        }
    }
}

Here's my appDelegate code which spawns 1 window on launch and 1 more every time a particular menu is selected:

    var windows: [Int:NSWindow] = [:]
    var windowCount = 0

    func applicationDidFinishLaunching(_ aNotification: Notification) {
        newWindow()
    }
    @IBAction func newFocusWindow(_ sender: NSMenuItem) {
        newWindow()
    }
    func newWindow() {
        windowCount = windowCount + 1
        let contentView = ContentView(windowCount: windowCount)
        let window = NSWindow(
            contentRect: NSRect(x: 100, y: 100, width: 1000, height: 1000),
            styleMask: [.titled, .closable, .miniaturizable, .resizable, .fullSizeContentView],
            backing: .buffered, defer: false)
        window.isReleasedWhenClosed = false
        windows[windowCount] = window
        window.title = "Focus Window \(self.windowCount)"
        window.tabbingMode = .disallowed
        window.center()
        //window.setFrameAutosaveName("Window \(self.windowCount)")
        window.contentView = NSHostingView(rootView: contentView)
        window.makeKeyAndOrderFront(nil)
    }

DebugPrint output shows that onFocusChange got called once per window:

2020-03-09 10:24:22.363001-0700 focusBug[2555:258395] Metal API Validation Enabled

"onFocusChange: true"

"onFocusChange: true"