QGraphicsPixmapItem/QGraphicsView bug?

QGraphicsPixmapItems pixmap moves by 1 pixel in random direction after changing screen resolution when being selected or unselected.
The pixmap is scaled inside constructor by code:
pixmap.scaled(h/2,h,Qt::KeepAspectRatio,Qt::SmoothTransformation);
setPixmap(pixmap);

Platform info:
OS: Win XP SP2
IDE: Visual Studio 2003
Qt: 4.5.0 commercial, VS Integrator 1.4.3

How to replicate the error:
I've created VS2003 project containing classes (it's in the attachment),but if you want create it by yourselves:
1.Create some window using the QGraphicsView I've provided in attachment
2.Create some cardItem objects and add them to scene.Place them near each other
3.Change the screen resolution to other.
4.Click onto the view and cards,as well as select them by holding LMB and mouse moving
5.You'll see strange behavior of moving items on scene-that's the issue I mean

I suspect that boundingRect is calculated incorrectly somehow,because you may sometimes see a 1 pxel space between card selection and card pixmap-just move one card over another.

Woops,the issue occurs event without resolution changing,as report project shows :/

OS: Win XP SP2
IDE: Visual Studio 2008 with add-In 1.1.2
Qt 4.6.0 Open Source

1.I create some QGraphicsPixmapItem inside dropEvent() of QGraphicsView
2.Inside constructor of pixmapItem I create a pixmap,then scale by use of:
pixmap=pixmap.scaled(h/2,h,Qt::KeepAspectRatio,Qt::SmoothTransformation);
setPixmap(pixmap);
3.Then I use new Qt 4.6.0 functions to rotate the item by 90 degrees:
setTransformOriginPoint(boundingRect().center());
setRotation(rotation()+90);//or -90

till now it works fine,BUT:
4.If I try to rotate the item by 180 degrees:
setTransformOriginPoint(boundingRect().center());
setRotation(rotation()+180);//or -180

Then the issue appears again.It is wasn't in Qt 4.5.0 during those rotations.
The strange thing is that bug during screen resolution change does not appear anymore in Qt 4.6.0

More Info:

Back in 4.5.0.
The issue appears mostly when an item is being selected using mouse dragging (QGraphicsView::RubberBandDrag mode is on).After close look there is a misplace of the qpixmapitem's pixmap start point-just like it is being moved by +1/+1 and -1/-1.
And some other hint:
setTransformationMode(Qt::SmoothTransformation);
inside the constructor of the pixmap item stops occurence of the bug (yet it causes another ones)