QT applications print with wrong paper type

This problem has been a reported unresolved problem for years. I see it reported here several times dating back to at least 2019. Shockingly remains unsolved to this day.

Attempting to print using any QT application always results in a printer error needing A4 sized paper despite Letter sized paper being selected and set everywhere.

Printing from any GTK application works fine.

 Work-around is to manually change the printer margins just before sending the print job. Must be manually adjusted each and every time for the trick to work. Setting any "working" margins permanently will fail on the next print job.

KDE Region setting is "Canada - Canadian English (en_CA)"

CUPS reports correct paper size as "Defaults:job-sheets=none, none media=na_letter_8.5x11in sides=two-sided-long-edge"

LC_PAPER reports correctly as "279 216 UTF-8"

Manually changing the paper size in the print dialogue window from Letter to (anything else) and back again has no effect.