Printing problem with October 2019 WS2012 CU - but not the usual one.

Question

We have a number of sites with WS2012 print servers. Two of them had printing problems after installing the 2021-09 CU (at one site; it doesn't have 2021-10 yet) and the 2021-10 CU (at the other site; it did not receive the 2021-09 update).

Welcome to the club, right? Well, these 2 sites have symptoms I've not seen discussed elsewhere.

1. I've read that only printers installed via Point & Print are affected. Neither site has Point & Print printers; all were installed by "Deploy Printers" in Print Management MSC.
2. No printers said "Driver update needed" in Settings/Devices and Printers, and no one was prompted to install a driver, with or without the temporary workaround described in https://support.microsoft.com/en-us/topic/kb5005652-manage-new-point-and-print-default-driver-installation-behavior-cve-2021-34481-873642bf-2634-49c5-a23b-6d8e9a302872.
3. The "Ports" tab in shared Printer properties on all the workstations (Windows 10 20H2 & 21H1) is completely empty. I've not seen this symptom described elsewhere in connection with the PrintNightmare fixes. Maybe I've just missed it? And notice where it says "Printer Name" instead of the name of the printer.
4. 
5. The temporary workaround described in https://support.microsoft.com/en-us/topic/kb5005652-manage-new-point-and-print-default-driver-installation-behavior-cve-2021-34481-873642bf-2634-49c5-a23b-6d8e9a302872 made no difference.
6. At one of the sites, UAC is turned off and all users are admins on their computers to accommodate a poorly-written LOB app. As such, they could point-and-print to their little hearts' content if they knew how.

When the CU is removed from the print server, the ports return, and printing resumes.

Is there anything I can do to avoid this when the next CU installs?