Multiple views in multiple views in multiple views painting behaviour

[Narf]

I'm doing research into creating an editor interface that works for a 3d node tree structure. The first thing I tried was to create a node (QGraphicsProxyWidget) with its own QGraphicsScene and a custom View. To quickly prototype I used the Chip example as a base. After a bit of mucking about but without modifying too much of the example code, I added a stripped down View class, created a few nodes and linked them up by putting lower level nodes into higher level scenes. The results can be seen in these pictures:

http://imageshack.us/f/38/gtx4.png/
http://imageshack.us/f/545/u028.png/

When zooming in or out with the seperate views an effect almost like z-fighting or clipping occurs where parts of the views disappear or otherwise appear to be unable to draw themselves. Dragging a selection box around invisible parts of the frames and chips forces them to be drawn, most of the time.

It appears to be entirely working apart from this bug. Does anyone here recognize the kind of render problems the views appear to be having and is there a known fix or workaround.