i was able to reproduce this upstream as well on an upgrade from pacific to master. still investigating
backport to upstream pacific merged: https://github.com/ceph/ceph/pull/42117
changes cherry picked downstream
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 (Red Hat Ceph Storage 5.0 bug fix and enhancement), 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/RHBA-2021:3294