Please run the the attached project. It's simply a QWebEngineView inside a QWidget.

#include <QtGui>
#include <QtWidgets>
#include <QtWebEngineWidgets>

int main(int argc, char *argv[])
{
    QApplication a(argc, argv);

    QWidget widget;

    QVBoxLayout *layout = new QVBoxLayout(&widget);

    QWebEngineView *view = new QWebEngineView;
    layout->addWidget(view);

    view->setUpdatesEnabled(false); // bang!

    widget.show();

    return a.exec();
}

If setUpdatesEnabled(false) is called on the QWebEngineView running on Mojave, and the Mac has an intel integrated GPU, the OS will kernel panic in the intel driver.

If setUpdatesEnabled(false) is replaced with hide(), it does not panic.

If the Mac has a dedicated GPU, it does not panic.

I also couldn't reproduce the panic when built with Qt 5.11.2 but it definitely happens with Qt 5.6.3 and most likely newer versions in between.