QGraphicsItem disappears when QGraphicsView transform has large scale factor

Under certain circumstances, I have found that QGraphicsPathItems are not drawn when I expect them to be. This occurs when the scale factor of the QGraphicsView transform is large (~1e8) on at least one axis, but also seems to be influenced by the size of the QGraphicsView as well. I have attached an example PyQt script (looks exactly the same under PySide) demonstrating the problem. The view shows three QGraphicsPathItems, two of which disappear as they move toward the edge of the view.

I would very much appreciate any suggestions for working around this problem--it has come up in a plotting library that I develop and I would like to be able to distribute a fix.