QLinearGradient painting not working properly on OpenVG paint engine during perspective tranformations

Perspective transformed painting of QLinearGradient works on OpenVG only if width == height. See attached QML file as example. The gradient in the front item in Flipable is painted as you would expect, the gradient in the back item is just drawn to solid black. Tested with Symbian^3. Does not reproduce when drawn with raster or opengl graphics systems.