Odd. Canon Printer MF731C/733C all of a sudden since BS and Catalina updates started to ask me to select a tray to print. Every time. I set in printer preferences US Letter as default on the Mac and same on the printer default letter multipurpose tray and even Tray 1. It keeps wanting me to select printer tray. I then did Custom present on my Macs and the default is alway A4 paper rather than letter. So I create a preset and and made sure its Letter instead of A4 as it shows default and now it prints ok without asking for selecting a tray on the printer screen. Anyone else experiencing this?

Source: https://forums.macrumors.com/threads/defaults-to-a4-paper-for-canon-laser-printers.2313968/