SwiftUI Sheet is only working once when opened from navigation bar - swift

Question

I have the problem that my sheet is not working as it should. When using a second NavigationView inside the SecondView then the sheet works but it looks crazy (first screenshot). When I comment out the NavigationView in SecondView the app looks correct (second screenshot), but the sheet is only working once when I open it from the Add button in navigation bar. When I use the "open sheet"-button in SecondView then the sheet works correct.
Did I do something wrong with this:
.navigationBarItems(trailing: Button("Add") {
showSheet.toggle()
})
SecondView with NavigationView:
SecondView without NavigationView (how it should look like):
This is the code I'm using:
import SwiftUI
struct ContentView: View {
var body: some View {
NavigationView {
VStack {
Text("Start View")
.font(.title)
NavigationLink(destination: SecondView()) {
CustomButton()
}
}
}
}
}
struct CustomButton: View {
var body: some View {
HStack {
Spacer()
Text("Go To Second View")
.font(.headline)
.foregroundColor(.red)
.padding()
Spacer()
}
.background(Color.white)
.overlay(
RoundedRectangle(cornerRadius: 20)
.stroke(Color.red, lineWidth: 2)
)
.padding()
}
}
struct SecondView: View {
#State private var showSheet = false
var body: some View {
//NavigationView{
Text("Second View")
Button("open sheet", action: {
showSheet.toggle()
})
.navigationBarBackButtonHidden(true)
.navigationBarItems(trailing: Button("Add") {
showSheet.toggle()
})
.sheet(isPresented: $showSheet, content: {
SecondViewsSheet()
})
//}
}
}
struct SecondViewsSheet: View {
var body: some View {
Text("Sheet")
.navigationBarItems(trailing: Button("Test"){
})
}
}
struct ContentView_Previews: PreviewProvider {
static var previews: some View {
ContentView()
}
}
I use Xcode 12.2 with an iPhone 12 Pro simulator.