Has anyone run into an issue like this before? I think it might actually be a SwiftUI bug. If you have code like the following, when you tap to present the sheet, it will actually fire the onAppear of the sheet view twice when openning and once again when closing:

struct TestView: View {
    var body: some View {
        VStack {
            SubTestView()
        }
    }
}

struct SubTestView: View {
    @State var present: Bool = false

    var body: some View {
        Text("Click me")
            .onTapGesture {
                present = true
            }
            .sheet(isPresented: $present, content: {
                Text("Sheet")
                    .onAppear {
                        print("Sheet presented")
                    }
            })
    }
}

#Preview {
    TabView {
        List {
            TestView()
        }
    }
}

However, if you don't nest the TestSubview in a container (VStack in this case), it will work correctly and only call onAppear once when the sheet appears. Also, to replicate the bug the List must be in a TabView. If you use a ScrollView with a VStack or LazyVStack inside instead of a List it will work correctly.

Something about the combination of TabView, List and the state being pushed down in a subview for the sheet to appear causes the issue. Or am I doing something silly?