Corruption in widgets after calling QWidget::winId

I'm experiencing some drawing issues, mostly in QDockWidget splitters and QTabWidgets after calling QWidget::winId on one of the widgets contained the central widget. I've attached some example images showing it working when not calling winId and not working after calling winId, along with the test application to reproduce the issue. I've also tried putting the call to winId in a QTimer to be called after 5 seconds, but I get the same behaviour once the timer finishes.