Okular (and Plasma Print Queue Manager) printing 4 sheets a page when asked to print 2

Operating System: Arch Linux
KDE Plasma Version: 6.7.4
KDE Frameworks Version: 6.29.0
Qt Version: 6.11.2
Kernel Version: 7.2.3-zen1-3-zen (64-bit)

When I ask Okular to print a PDF one page per sheet, it does it fine.

When I ask Okular to print a PDF two pages per sheet, left to right, top to bottom, duplex on short edge, it instead prints 4 pages per sheet, duplex short edge, thus:
3 4
1 2
…so not booklet, just the wrong number of pages in the wrong order.

Other software, e.g. LibreOffice, prints two per sheet, duplex short edge, just as asked. So it’s not the printer, and not the Plasma Print Queue Manager alone.

How do I get Okular to print the right number of pages per sheet?