Is automatic nvidia driver installation with secure boot broken in ubuntu 20.04.3

Has the automated installation of nvidia drivers broken with the latest ubuntu 20.04/xubuntu 20.04 installs in the case of a secure boot computer?

Background: I have used ubuntu and xubuntu for at least 10 years on various desktops, servers and laptops. I have a laptop which is required to be in secure boot mode because of secure/encrypted windows. This laptop (Aero15x 2017, GTX 1070) with a discrete nvidia GPU which has run beautifully for years on 18.04 and 20.04 with periodic updates of the nvidia drivers automatically and without problem.

However in January, I assume after an update of al the packages (I believe including nvidia-driver-510.) It stopped booting. Grub comes up as usually, but when I selected the usual latest kernel the first two lines of the boot come up including loading the initramfs then locking up before the "Secure Boot" message. I tried various repairs using a live usb of ubuntu 20.04 and xbuntu 20.04, both of which boot without difficulty using the nouveau driver.

I ultimately reinstalled first the latext ubuntu 20.04 then the latest xubuntu 20.04 and both install without difficulty. but when I use the "install additional drivers option" in the graphical software management panel, the lockup returns. I tried this with several versions of the driver (510, 470) and with several kernels that could be installed.

Ultimately it looks like the usual automatic signing/enrollment process is not happening. I came up with a work around by download the runfile version of the nvidia driver (510) from the nvidia website and did a command line install and selected the "sign driver" option then used "MOK" to add the signature to my secureboot nvram after reboot.

My steps to make it work with secure boot were as follows:

sudo apt-get update
sudo apt-get upgrade

I pressed then a menu labeled as "Perform MOK Management" appeared, there were the following four options:

1 . Continue boot 2 . Enroll Key 3 . Enroll Key from Disk 4 . EnrollKey from Hash

I chose option number 2, then I continued to boot, it finally worked, I went to Ubuntu settings->Details and my Graphic Card name was shown correctly.