PDF output is resolution-dependent with ItemIgnoresTransformations

When a QGraphicsScene is rendered with a QPainter that draws onto a QPrinter (with PDF format set on it), any QGraphicsItems in the scene that have the ItemIgnoresTransformations flag set on them will only appear correctly (i.e.: the same way as they do on the screen in a QGraphicsView) if a specific resolution (in this case 75 DPI) is set on the QPrinter.
With any other resolution, the affected items are scaled relative to the rest of the scene.
See the attached demo and some of its outputs.
All the mentioned Qt versions are affected.
Not tested this on any other platform.

I think https://bugreports.qt.io/browse/QTBUG-24328 might be related.

(EDIT: corrected class name)