When a QStandardItemModel is destroyed and the execution reaches the ~QObject() destructor, it goes on to clean all of the QObject children, including the top-level QStandardItemModel instances. Their respective destructors ~QStandardItemPrivate calls setModel(0) on all of their children.

QStandardItemModel::setModel, however, calls back to the original model's invalidatePersistentIndex. This is undefined behavior because the ~QStandardItemModel has already finished, and that object is not even QObject anymore.