QFileDialog drive icons incorrect scaling on screen with non-integer device pixel ratio

QFileDialog shows incorrectly rendered drive icons on screen with non-integer device pixel ratio (without pass-through scaling). The icon for "My Computer" and folder icons appear correct.

To reproduce, compile and execute attached code and run under Windows (10) with a font scaling of 150%. Then select "My Computer" from the dialog's combo box and then select a drive. The combo box shows a distorted drive icon. See attached screenshot.

Note that the code uses a proxy style to generate 'larger than default' icons.