Issue repmgr 5.2.1 switchover postgres 12 on RHEL8 SELinux enforcing

Hi,

I have an issue with postgresql & repmgr on RHEL8.
I have installed postgres 12 and repmgr 5.2.1 on two RHEL8 servers with
SELinux in enforcing mode.
The installation went fine and a switchover dry-run seems ok:

[postgresql(at)serverb ] $ $/usr/pgsql-12/bin/repmgr standby
switchover -f /data/repmgr.conf --dry-run
NOTICE: checking switchover on node "serverb" (ID: 2) in --dry-run
mode
INFO: SSH connection to host "servera" succeeded
INFO: able to execute "repmgr" on remote host "servera"
INFO: 1 walsenders required, 5 available
INFO: demotion candidate is able to make replication connection to
promotion candidate
INFO: 0 pending archive files
INFO: replication lag on this standby is 0 seconds
NOTICE: local node "serverb" (ID: 2) would be promoted to primary;
current primary "servera" (ID: 1) would be demoted to standby
INFO: following shutdown command would be run on node "servera":
"/usr/pgsql-12/bin/pg_ctl -D $PGDATA stop -m fast"
INFO: parameter "shutdown_check_timeout" is set to 60 seconds
INFO: prerequisites for executing STANDBY SWITCHOVER are met

But when I start the switchover I get this:
postgresql(at)serverb ] $ /usr/pgsql-12/bin/repmgr standby switchover -f
/data/repmgr.conf --dry-run
NOTICE: executing switchover on node "serverb" (ID: 2)
NOTICE: local node "serverb" (ID: 2) will be promoted to primary; current
primary "servera" (ID: 1) will be demoted to standby
NOTICE: stopping current primary node "servera" (ID: 1)
NOTICE: issuing CHECKPOINT on node "servera" (ID: 1)
DETAIL: executing server command "/usr/pgsql-12/bin/pg_ctl -D $PGDATA stop
-m fast"
INFO: checking for primary shutdown; 1 of 60 attempts
("shutdown_check_timeout")
INFO: checking for primary shutdown; 2 of 60 attempts
("shutdown_check_timeout")
...
INFO: checking for primary shutdown; 59 of 60 attempts
("shutdown_check_timeout")
INFO: checking for primary shutdown; 60 of 60 attempts
("shutdown_check_timeout")
ERROR: shutdown of the primary server could not be confirmed
HINT: check the primary server status before performing any further actions

Are there known issues with postgres 12 and repmgr 5.2.1 with RHEL8 and
SELINUX in enforcing mode?
Any suggestions on how to proceed with debugging?

Thanks in advance.

Regards
Mariane