QGraphicsEffect::sourcePixmap render error when scaling to a extend

When applying QGraphicsEffect and scaling the QGraphicsView to some extend, the sourcePixmap function render failed and produce the following message:

QPainter::begin: Paint device returned engine == 0, type: 2
QPainter::setRenderHint: Painter must be active to set rendering hints
QPainter::setWorldTransform: Painter not active
QPainter::setOpacity: Painter not active
QPainter::setPen: Painter not active
QPainter::setBrush: Painter not active
QPainter::drawPath: Painter not active
QPainter::end: Painter not active, aborted

While if we disable QGraphicsEffect, we can scale the graphics view to infinite extend.
The attached file is a simple program showing this problem, scaling the graphics view further more you will see the error message and the render error. In the demo I use QGraphicsOpacityEffect which calls sourcePixmap() internally to illustrate the problem.