[Windows]: "External WM_DESTROY received for..." message sent when deleting a window after reparenting one of its child windows

When calling deleteLater() on a top level QWidget after it has just reparented a child top level widget to its own parent then it will trigger the message:

"5.7.0 windows"
MainWindow(0x2dfd3bfaa0) on QWidget(0x0)
MainWindow(0x22db8c38d70) on MainWindow(0x2dfd3bfaa0, name="MainWindow0")
MainWindow::on_createChildButton_clicked MainWindow(0x22db8c38d70, name="MainWindow1")
MainWindow(0x22dbbc98cd0) on MainWindow(0x22db8c38d70, name="MainWindow1")
MainWindow::on_createChildButton_clicked MainWindow(0x22dbbc98cd0, name="MainWindow2")
MainWindow::on_deleteSelfButton_clicked >reparenting MainWindow(0x22dbbc98cd0, name="MainWindow2") to MainWindow(0x2dfd3bfaa0, name = "MainWindow0")
MainWindow::on_deleteSelfButton_clicked >deleteLater
MainWindow::on_deleteSelfButton_clicked <
MainWindow::~MainWindow "MainWindow1"
External WM_DESTROY received for QWidgetWindow(0x22dbbc92720, name="MainWindow2Window") , parent: QWindow(0x0) , transient parent: QWidgetWindow(0x22db8c129a0, name="MainWindow0Window")
...
MainWindow::~MainWindow "MainWindow0"
MainWindow::~MainWindow "MainWindow2"

This does not happen if the child is not reparented before hand. So if you have a chain of widgets all top level like:

A which is a parent of B which is a parent of C

then reparent C to be a child of A and call deleteLater() on B it will trigger the message.