There's an HP MFP M127fn printer on the LAN. Regardless of how many copies the print command is executed with, it only prints a single copy.
This issue wasn't always around; I used to run Debian testing and a month or two back this change occurred and the printer no longer prints multiple copies. Later I moved to Kubuntu, still the printer behaved the same.
Print commands from Windows outputs normally, so I concluded it's a Linux/CUPS issue. How do I diagnose and hopefully workaround, if not fix, this issue?
PS The print queue shows the number of copies the command was executed with.
EDIT Since this question hasn't been getting much attention, I'd like to bump by adding that Android devices with the builtin print thingy was able to successfully print the proper number of pages.