The issue is still reproducible with tuned-2.14.0-3.el8.noarch, but the error is a bit different:

2020-09-02 11:14:26,870 ERROR    tuned.plugins.plugin_script: script '/usr/lib/tuned/cpu-partitioning/script.sh' error output: 'Unit ksm.service does not exist, proceeding anyway.
Unit ksmtuned.service does not exist, proceeding anyway.'

We should be able to fix it with a similar patch as posted here
https://bugzilla.redhat.com/show_bug.cgi?id=1591431#c2

===
# systemctl mask ksm ksmtuned
Unit ksm.service does not exist, proceeding anyway.
Unit ksmtuned.service does not exist, proceeding anyway.
Created symlink /etc/systemd/system/ksm.service → /dev/null.
Created symlink /etc/systemd/system/ksmtuned.service → /dev/null.

# systemctl unmask ksm ksmtuned
Removed /etc/systemd/system/ksm.service.
Removed /etc/systemd/system/ksmtuned.service.
#
===

* Above error is reported by systemctl(1) if ksm/ksmtuned services are not installed.

* ksm/ksmtuned services are installed via qemu-kvm-common package
  qemu-kvm-common package is installed as dependency for qemu-kvm package

   qemu-kvm -> qemu-kvm-core -> qemu-kvm-common

* Above error is unlikely to occur on virt-rt systems which will have
  above packages installed.

* Recent tuned(8) upstream change removes usage of enable_ksm/disable_ksm functions
  from -realtime profile

* ie. this issue does does not seem relevant for RHEL-8/virt-rt scenario.

* A possible solution is to define 'qemu-kvm-common' package as 'Requirement'
  for tuned-profiles package which use ksm, ksmtuned services.

* Closing this bug here.