SwiftUI navigation bar button color changes depending on whether the root view is a ScrollView or VStack

I have a SwiftUI view inside a NavigationStack with a custom navigation bar background color. I want the navigation bar buttons to have a consistent color throughout the app.

The issue is that the navigation bar button color changes depending on the first/root view in the body.

When the root view is a ScrollView

var body: some View {
    ScrollView {
        // content
    }
    .toolbarBackground(Color(red: 0.02, green: 0.27, blue: 0.13), for: .navigationBar)
    .toolbarBackground(.visible, for: .navigationBar)
    .toolbarColorScheme(.dark, for: .navigationBar)
}

The navigation bar buttons appear white.

However, if I replace the ScrollView with a VStack, while keeping the same modifiers, the navigation bar buttons appear black:

var body: some View {
    VStack {
        // content
    }
    .toolbarBackground(Color(red: 0.02, green: 0.27, blue: 0.13), for: .navigationBar)
    .toolbarBackground(.visible, for: .navigationBar)
    .toolbarColorScheme(.dark, for: .navigationBar)
}

The navigation bar buttons appear black.

How can I make the navigation bar buttons stay the same colour in both cases?