Margin settings are ignored unless Printer Properties dialog is opened first

I reported the following problem on the KDE bug tracker <https://bugs.kde.org/show_bug.cgi?id=256975> and was told that this is an issue not with KDE but with the Qt print dialog, so I am reproducing it here.

When printing (to PDF or PostScript; I haven't tested this with an actual printer as I don't have one), the margin settings are ignored, and KDE uses ridiculously small margins. However, if, before printing, you click on the "Properties" button next to the selected printer, a dialog will pop up allowing you to adjust the margins. Just click on "OK" or "Cancel" (there's no need to actually change any settings); then when you print the margin settings will be used.

Reproducible: Always

Steps to Reproduce:
1. File->Print
2. Printer->Name->Print to File (PDF) or Printer->Name->Print to File (Postscript)
3. Print

Actual Results:
4. The output file has very narrow margins, regardless of what the actual margin settings were.

Expected Results:
4. The output file should have had the same margins specified in the Printer's Properties dialog.

To work around, insert the following steps:

2a. Properties
2b. Cancel