REG->dev: Application hangs when calling close on hidden window via timer

I am not sure if this is a real bug or intended change of behaviour, but at f2de001d8410b85047ee40ebfff1b307a18889bb , the code

    QApplication a(argc, argv);
    QWidget w;
   //    w.show();
    QTimer::singleShot(0, &w, &QWidget::close);
    return  a.exec();

hangs. Note the widget is not shown. The app terminates normally when calling show().

The attached sample produces

Qt 6.3.0 (x86_64-little_endian-lp64 shared (dynamic) debug build; by GCC 9.3.0)
Timer running

vs

Qt 6.2.0 (x86_64-little_endian-lp64 shared (dynamic) debug build; by GCC 9.3.0)
Timer running
Exit 0

Manifested in a Qt for Python test