When using QEvenLoop and Network stack, _q_startOperation seems to be called multiple times

Hi.

When upgrading to 5.12.0 from 5.11.3, a new debug message from Qt appears:

QNetworkReplyHttpImplPrivate::_q_startOperation was called more than once QUrl

To reproduce the behaviour:

• create a default "Application Qt with widgets"
• add in the .pro file

      QT       += network
  

• copy/paste the following code as mainwindow.cpp

  #include "mainwindow.h"
  #include "ui_mainwindow.h"
  
  #include <QNetworkReply>
  #include <QNetworkAccessManager>
  auto networkAccessManager = new QNetworkAccessManager;
  QEventLoop* loop;
  MainWindow::MainWindow(QWidget *parent) :
    QMainWindow(parent),
    ui(new Ui::MainWindow)
  {
    ui->setupUi(this);
    loop = new QEventLoop;
    connect(networkAccessManager, &QNetworkAccessManager::finished, [&](QNetworkReply* reply)
    {
      //qDebug("%s", qUtf8Printable(reply->readAll()));
      //reply->deleteLater();
      //loop->quit();
      //loop->deleteLater();
      //loop = nullptr;
    });
    networkAccessManager->get(QNetworkRequest(QUrl("http://google.fr")));
    loop->exec();
  }
  
  MainWindow::~MainWindow()
  {
    delete ui;
  }
  

The behaviour is consistant across platforms, and doesn't depend on my code as it is triggered between the exec call and the signal emission.