confirmationDialog crashes with Button.init(action, @ViewBuilder label)

My app gets killed with the error message: Actions added to UIAlertController of style UIAlertActionStyleDefault must have a title when running in UIUserInterfaceIdiomPhone

if I use one sort of button, but not the shorter sort. This code produces the error, but it I remove the button with Image(systemName:) I get that error.

Button(action: { showingExtras = true } ) { 
   Image(systemName: "ellipsis.rectangle") 
}
  .confirmationDialog("Extras", isPresented: $showingExtras) {
    Button(action: { showingCashSummary = true} )  {
      Image(systemName: "banknote")
    }
    Button("Cash summary") { showingCashSummary = true }
    Button("Allocation summary") {showingAllocationSummary = true}
    Button("Export") { isExporting = true }
}

Is there some way to add the title that UIAlertController requires?