I did see that update today, but did not yet install as I was wondering if I would run into the same issue. Now below is a list of everything I had tried in my troubleshooting process. Not sure if any of this will help. One other quick note, I had already register my key in the past as well, but re-enrolling is what fixed the initial issue for me.
List of step taken from forum and other sites.
* sudo apt-get purge 'nvidia*' or sudo apt autoremove nvidia* --purge
* sudo add-apt-repository ppa:damentz/liquorix
* sudo add-apt-repository ppa:graphics-drivers/ppa
* sudo apt update
* sudo ubuntu-drivers devices
** driver : nvidia-driver-545 - third-party non-free recommended
* sudo ubuntu-drivers autoinstall or install through GUI (make sure it is the version you want to install 3rd party non-free
* sudo apt install --reinstall linux-headers-$(uname -r)
* sudo mokutil --import /var/lib/shim-signed/mok/MOK.der
** Set the password in the configure secure boot stage, and remember your password
reboot system
Operation steps in MOK screen
If you enter the screen of Perform MOK management, please select Enroll MOK > Continue > Yes
Enter the password at the screen of Enroll the key(s)?
Select OK to reboot
After rebooting, nvidia-smi command worked.