As been spotted in https://github.com/openshift/assisted-service/pull/2152#discussion_r663495149, the docs are not completely clear that it's the BMAC setting the value of the automatedCleaningMode for the BMH.
Verified
Since the problem described in this bug report should be resolved in a recent advisory, it has been closed with a resolution of ERRATA. For information on the advisory (Moderate: OpenShift Container Platform 4.9.0 bug fix and security update), and where to find the updated files, follow the link below. If the solution does not work for you, open a new bug report. https://access.redhat.com/errata/RHSA-2021:3759