Here is a simple one, maybe. Why does this simple code to disable edit produce the following run time error...

Modifying state during view update, this will cause undefined behavior.

struct ContentView: View {

    @State private var someWord = ""
    @State private var editDisable = false

    var body: some View {
        VStack {
            TextField("", text: $someWord)
                .font(.title)
                .padding()
                .background(Color.cyan)
                .disabled(editDisable)
            Toggle(isOn: $editDisable) {
                Text("Disable Edit")
            }
            .font(.title)
            .padding()
        }
    }
}

Is there another way of doing it?

Check out How to fix “Modifying state during view update, this will cause undefined behavior”.