OpenXChange machine.secret not set after univention-join

UCS 4.4.6
OX AppSuite 7.10.4-ucs1

On a UCS Backup (AD Controller) with OpenXChange a new join of the system will result in a new /etc/machine.secret

root@backup:~# ls -all /etc/machine.secret*
-rw------- 1 root root 20 Okt 22 08:31 /etc/machine.secret
-rw------- 1 root root 1683 Okt 1 01:01 /etc/machine.secret.old
-rw------- 1 root root 280 Okt 22 08:31 /etc/machine.secret.SAVE

With that secret i am able to auth against ldap.

But somehow this password is not updated for OpenXChange

root@backup:~# cat /etc/machine.secret
EJ815Pm1W27ZcvlRTOTn

root@backup:~# tail -1 /opt/open-xchange/etc/authplugin.properties
com.openexchange.authentication.ucs.bindPassword=p0wylWa2xcLcyTu7bLLm

root@backup:~# ucr search bindPassword
com.openexchange.authentication.ucs.bindPassword: e7dHDj2mJQaZpqxUZZ2D

ox/cfg/authplugin.properties/com.openexchange.authentication.ucs.bindPassword: @&@/etc/machine.secret@&@

Enter DC Master Account : Administrator
Enter DC Master Password:

Search DC Master: done
Check DC Master: done
Stop S4-Connector: done
Stop LDAP Server: done
Stop Samba Server: done
Search ldap/base done
Start LDAP Server: done
Search LDAP binddn done
Sync time: done
Running pre-join hook(s): done
Join Computer Account: done
Stopping univention-directory-notifier daemon: done
Stopping univention-directory-listener daemon: done
Sync ldap.secret: done
Sync ldap-backup.secret: done
Sync SSL directory: done
Check TLS connection: done
Download host certificate: done
Sync SSL settings: done
Purging translog database: done
Restart LDAP Server: done
Sync Kerberos settings: done
Not updating kerberos/adminserver
Running pre-joinscripts hook(s): done
Configure 01univention-ldap-server-init.inst done
Configure 02univention-directory-notifier.inst done
Configure 03univention-directory-listener.inst done
Configure 04univention-ldap-client.inst done
Configure 05univention-bind.inst done
Configure 08univention-apache.inst done
Configure 10univention-ldap-server.inst done
Configure 11univention-heimdal-init.inst done
Configure 11univention-pam.inst done
Configure 15univention-directory-notifier-post.inst done
Configure 15univention-heimdal-kdc.inst done
Configure 18python-univention-directory-manager.inst done
Configure 20univention-directory-policy.inst done
Configure 20univention-join.inst done
Configure 20univention-ldap-config-master.inst done
Configure 22univention-directory-manager-rest.inst done
Configure 26univention-nagios-common.inst done
Configure 30univention-appcenter.inst done
Configure 30univention-nagios-client.inst done
Configure 31univention-nagios-s4-connector.inst done
Configure 31univention-nagios-samba.inst done
Configure 33univention-portal.inst done
Configure 34univention-management-console-server.inst done
Configure 34univention-self-service.inst done
Configure 35univention-appcenter-docker.inst done
Configure 35univention-management-console-module-appcenter.done
Configure 35univention-management-console-module-diagnosticdonet
Configure 35univention-management-console-module-ipchange.idone
Configure 35univention-management-console-module-join.inst done
Configure 35univention-management-console-module-lib.inst done
Configure 35univention-management-console-module-mrtg.inst done
Configure 35univention-management-console-module-quota.instdone
Configure 35univention-management-console-module-reboot.insdone
Configure 35univention-management-console-module-services.idone
Configure 35univention-management-console-module-setup.instdone
Configure 35univention-management-console-module-sysinfo.indone
Configure 35univention-management-console-module-top.inst done
Configure 35univention-management-console-module-ucr.inst done
Configure 35univention-management-console-module-udm.inst done
Configure 35univention-management-console-module-updater.indone
Configure 35univention-self-service-passwordreset-umc.inst done
Configure 35univention-server-overview.inst done
Configure 36univention-management-console-module-apps.inst done
Configure 38univention-management-console-module-oxldb.instdone
Configure 40univention-postgresql.inst done
Configure 40univention-virtual-machine-manager-schema.inst done
Configure 65univention-ox.inst done
Configure 67univention-mail-server.inst done
Configure 81univention-nfs-server.inst done
Configure 82univention-mail-dovecot.inst done
Configure 90univention-bind-post.inst done
Configure 91univention-saml.inst done
Configure 92univention-management-console-web-server.inst done
Configure 96univention-samba4.inst done
Configure 97univention-s4-connector.inst done
Configure 98univention-pkgdb-tools.inst done
Configure 98univention-samba4-dns.inst done
Configure 98univention-samba4-saml-kerberos.inst done
Running post-joinscripts hook(s): done

root@backup:~# univention-check-join-status
Joined successfully

I was checking the join.log but cant find anything useful (at least for me). What is a good way to debug this issue?