I did a quick test with apparmor focal-yoga and -proposed this morning to verify it fixes https://bugs.launchpad.net/cloud-archive/+bug/1988270 

# testing with focal-yoga 
Apparmor version tested -  2.13.3-7ubuntu5.2

generate focal-yoga instance 
juju ssh nova-compute/0 

sudo apt-cache policy apparmor
sudo vim /etc/apt/sources.list
# add -proposed
deb http://nova.clouds.archive.ubuntu.com/ubuntu/ focal-proposed main universe
# save and exit 
sudo apt-get upgrade apparmor
sudo systemctl restart apparmor
tail -n 1000 /var/log/syslog 

# no errors are thrown by apparmor 
Jan  9 15:27:40 juju-3151fe-testapparmor-9 apparmor.systemd[62260]: Restarting AppArmor
Jan  9 15:27:40 juju-3151fe-testapparmor-9 apparmor.systemd[62260]: Reloading AppArmor profiles
Jan  9 15:27:40 juju-3151fe-testapparmor-9 apparmor.systemd[62274]: Skipping profile in /etc/apparmor.d/disable: usr.bin.nova-compute
Jan  9 15:27:40 juju-3151fe-testapparmor-9 kernel: [ 1440.404862] audit: type=1400 audit(1673278060.118:74): apparmor="STATUS" operation="profile_replace" info="same as current profile, skipping" profile="unconfined" name="virt-aa-helper" pid=62273 comm="apparmor_parser"
Jan  9 15:27:40 juju-3151fe-testapparmor-9 kernel: [ 1440.406888] audit: type=1400 audit(1673278060.118:75): apparmor="STATUS" operation="profile_replace" info="same as current profile, skipping" profile="unconfined" name="/usr/bin/man" pid=62275 comm="apparmor_parser"
Jan  9 15:27:40 juju-3151fe-testapparmor-9 kernel: [ 1440.406890] audit: type=1400 audit(1673278060.118:76): apparmor="STATUS" operation="profile_replace" info="same as current profile, skipping" profile="unconfined" name="man_filter" pid=62275 comm="apparmor_parser"
Jan  9 15:27:40 juju-3151fe-testapparmor-9 kernel: [ 1440.406892] audit: type=1400 audit(1673278060.118:77): apparmor="STATUS" operation="profile_replace" info="same as current profile, skipping" profile="unconfined" name="man_groff" pid=62275 comm="apparmor_parser"
Jan  9 15:27:40 juju-3151fe-testapparmor-9 kernel: [ 1440.408833] audit: type=1400 audit(1673278060.122:78): apparmor="STATUS" operation="profile_replace" info="same as current profile, skipping" profile="unconfined" name="/usr/lib/snapd/snap-confine" pid=62276 comm="apparmor_parser"
Jan  9 15:27:40 juju-3151fe-testapparmor-9 kernel: [ 1440.408838] audit: type=1400 audit(1673278060.122:79): apparmor="STATUS" operation="profile_replace" info="same as current profile, skipping" profile="unconfined" name="/usr/lib/snapd/snap-confine//mount-namespace-capture-helper" pid=62276 comm="apparmor_parser"
Jan  9 15:27:40 juju-3151fe-testapparmor-9 kernel: [ 1440.415917] audit: type=1400 audit(1673278060.130:80): apparmor="STATUS" operation="profile_replace" info="same as current profile, skipping" profile="unconfined" name="/usr/lib/NetworkManager/nm-dhcp-client.action" pid=62277 comm="apparmor_parser"
Jan  9 15:27:40 juju-3151fe-testapparmor-9 kernel: [ 1440.415921] audit: type=1400 audit(1673278060.130:81): apparmor="STATUS" operation="profile_replace" info="same as current profile, skipping" profile="unconfined" name="/usr/lib/NetworkManager/nm-dhcp-helper" pid=62277 comm="apparmor_parser"
Jan  9 15:27:40 juju-3151fe-testapparmor-9 kernel: [ 1440.415924] audit: type=1400 audit(1673278060.130:82): apparmor="STATUS" operation="profile_replace" info="same as current profile, skipping" profile="unconfined" name="/usr/lib/connman/scripts/dhclient-script" pid=62277 comm="apparmor_parser"
Jan  9 15:27:40 juju-3151fe-testapparmor-9 kernel: [ 1440.415926] audit: type=1400 audit(1673278060.130:83): apparmor="STATUS" operation="profile_replace" info="same as current profile, skipping" profile="unconfined" name="/{,usr/}sbin/dhclient" pid=62277 comm="apparmor_parser"
Jan  9 15:27:40 juju-3151fe-testapparmor-9 apparmor.systemd[62279]: Skipping profile in /etc/apparmor.d/disable: usr.sbin.rsyslogd
Jan  9 15:27:40 juju-3151fe-testapparmor-9 systemd[1]: Finished Load AppArmor profiles.