When calling QProcess::startDetached to start cmd.exe the process starts but the command line window does not appear

I have a simple Qt project (see attachment) to start a detached process on start up for cmd.exe

#include <cassert>


#include <QProcess>


#include "mainwindow.h"
#include "ui_mainwindow.h"


MainWindow::MainWindow(QWidget *parent) :
    QMainWindow(parent),
    ui(new Ui::MainWindow)
{
    ui->setupUi(this);


    QProcess p;


    bool ok = p.startDetached("C:/Windows/system32/cmd.exe");
    assert(ok);
}


MainWindow::~MainWindow()
{
    delete ui;
}

When I build this project using Qt Creator with Qt 5.6.3 it works as expected; the command line window is displayed on application start up.

When I switch over to build the project using Qt 5.9.1 or 5.9.2, the command line window is not displayed on application start up. However, I can see that the cmd.exe process has indeed started as it is listed in the Task Manager. I can see this behaviour when using either VS 2013 or 2017 compilers.