IPP printer page size not available in Windows

I am working for a printer manufacturer and adding IPP support to our small form factor printers which print on 57mm paper roll. The printer works when connected to Linux, but when connected to Windows (10 or 11), the paper size is not showing as an available size (In Print Preferences etc) - only A4 and Legal seem to be available. Any ideas why Windows seems to not allow the small paper size that our printer supports?

Question by user2073948 on Super User, licensed CC BY-SA. We show a short excerpt and link to the original thread as credit.