QGraphicsProxyWidget move when showing after minimization

I'm using GraphicsView and have added a QPushButton to my scene through a graphics proxy widget, aka:

QGraphicsProxyWidget* item = scene.addWidget(new QPushButton("Sadly, I tend to move"));
item->setPos(pivot);

If you minimize the window using the yellow minimize button on OSX, then re showing the window the button within the history view moves to the top left. If I have multiple buttons thye all move to the top left. This is quite annoying since they are precisely placed next to relevant content.