Memory corruption because of reused submenu

==5569== Invalid read of size 1
==5569==    at 0x51D68D4: QMenuSloppyState::childLeave() (qmenu.cpp:778)
==5569==    by 0x51D68B3: QMenuSloppyState::leave() (qmenu.cpp:771)
==5569==    by 0x51D90BE: QMenuPrivate::mouseEventTaken(QMouseEvent*) (qmenu.cpp:1342)
==5569==    by 0x51DDEC3: QMenu::mouseReleaseEvent(QMouseEvent*) (qmenu.cpp:2891)
==5569==    by 0x5026DBC: QWidget::event(QEvent*) (qwidget.cpp:8631)
==5569==    by 0x51DE81C: QMenu::event(QEvent*) (qmenu.cpp:3030)
==5569==    by 0x4FDCD4A: QApplicationPrivate::notify_helper(QObject*, QEvent*) (qapplication.cpp:3693)
==5569==    by 0x4FDA88B: QApplication::notify(QObject*, QEvent*) (qapplication.cpp:3137)
==5569==    by 0x66A5D4D: QCoreApplication::notifyInternal2(QObject*, QEvent*) (qcoreapplication.cpp:1092)
==5569==    by 0x66A66E3: QCoreApplication::sendSpontaneousEvent(QObject*, QEvent*) (qcoreapplication.cpp:1499)
==5569==    by 0x4FD92CE: QApplicationPrivate::sendMouseEvent(QWidget*, QMouseEvent*, QWidget*, QWidget*, QWidget**, QPointer<QWidget>&, bool, bool) (qapplication.cpp:2623)
==5569==    by 0x5055E64: QWidgetWindow::handleMouseEvent(QMouseEvent*) (qwidgetwindow.cpp:572)
==5569==  Address 0x181b5274 is 708 bytes inside a block of size 832 free'd
==5569==    at 0x4C2D31B: operator delete(void*) (in /usr/lib/valgrind/vgpreload_memcheck-amd64-linux.so)
==5569==    by 0x51E3740: QMenuPrivate::~QMenuPrivate() (qmenu_p.h:326)
==5569==    by 0x66F54FF: QScopedPointerDeleter<QObjectData>::cleanup(QObjectData*) (qscopedpointer.h:60)
==5569==    by 0x66F2968: QScopedPointer<QObjectData, QScopedPointerDeleter<QObjectData> >::~QScopedPointer() (qscopedpointer.h:107)
==5569==    by 0x66E78A6: QObject::~QObject() (qobject.cpp:997)
==5569==    by 0x5012725: QWidget::~QWidget() (qwidget.cpp:1408)
==5569==    by 0x51DA1AF: QMenu::~QMenu() (qmenu.cpp:1704)
==5569==    by 0x10AFE5: MainWindow::MainWindow(QWidget*)::{lambda(QPoint const&)#2}::operator()(QPoint const&) const (mainwindow.cpp:21)
==5569==    by 0x10B752: QtPrivate::FunctorCall<QtPrivate::IndexesList<0>, QtPrivate::List<QPoint const&>, void, MainWindow::MainWindow(QWidget*)::{lambda(QPoint const&)#2}>::call({lambda(QPoint const&)#2}&, void**) (qobjectdefs_impl.h:146)
==5569==    by 0x10B6F0: void QtPrivate::Functor<MainWindow::MainWindow(QWidget*)::{lambda(QPoint const&)#2}, 1>::call<QtPrivate::List<QPoint const&>, void>({lambda(QPoint const&)#2}&, void*, {lambda(QPoint const&)#2}&*) (qobjectdefs_impl.h:256)
==5569==    by 0x10B694: QtPrivate::QFunctorSlotObject<MainWindow::MainWindow(QWidget*)::{lambda(QPoint const&)#2}, 1, QtPrivate::List<QPoint const&>, void>::impl(int, QtPrivate::QSlotObjectBase*, QObject*, void**, bool*) (qobjectdefs_impl.h:439)
==5569==    by 0x66B6FBA: QtPrivate::QSlotObjectBase::call(QObject*, void**) (qobjectdefs_impl.h:394)