samba-ad-dc error 110 after reboot

I have a raspberry PI 400 where I try to install samba-ad-dc.
I have a dns server on this machine. named an samba-ad-dc services are enabled
I see that after a reboot the status for samba-ad-dc.service shows an error:

Jun 28 02:00:50 rasp mitkdc[1755]: [2021/06/28 02:00:50.132497,  0] ../../lib/util/util_runcmd.c:352(samba_runcmd_io_handler)
Jun 28 02:00:50 rasp mitkdc[1755]:   /usr/sbin/krb5kdc: krb5kdc: starting...
Jun 28 02:00:50 rasp winbindd[1771]: [2021/06/28 02:00:50.168658,  0] ../../source3/winbindd/winbindd_cache.c:3204(initialize_winbindd_cache)
Jun 28 02:00:50 rasp winbindd[1771]:   initialize_winbindd_cache: clearing cache and re-creating with version number 2
Jun 28 02:00:50 rasp winbindd[1771]: [2021/06/28 02:00:50.216400,  0] ../../lib/util/become_daemon.c:152(daemon_ready)
Jun 28 02:00:50 rasp winbindd[1771]:   daemon_ready: daemon 'winbindd' finished starting up and ready to serve connections
Jun 28 02:00:50 rasp smbd[1745]: [2021/06/28 02:00:50.478637,  0] ../../lib/util/become_daemon.c:152(daemon_ready)
Jun 28 02:00:50 rasp smbd[1745]:   daemon_ready: daemon 'smbd' finished starting up and ready to serve connections
Jul 06 09:08:53 rasp samba[1776]: [2021/07/06 09:08:53.117027,  0] ../../source4/dsdb/dns/dns_update.c:85(dnsupdate_nameupdate_done)
Jul 06 09:08:53 rasp samba[1776]:   dnsupdate_nameupdate_done: Failed DNS update with exit code 110

If I do a “systemctl restart samba-ad-dc” then the status shows no error

Jul 06 15:18:46 rasp mitkdc[4438]: [2021/07/06 15:18:46.515178,  0] ../../lib/util/util_runcmd.c:352(samba_runcmd_io_handler)
Jul 06 15:18:46 rasp mitkdc[4438]:   /usr/sbin/krb5kdc: Stash file (null) uses DEPRECATED enctype !
Jul 06 15:18:46 rasp mitkdc[4438]: [2021/07/06 15:18:46.584966,  0] ../../lib/util/util_runcmd.c:352(samba_runcmd_io_handler)
Jul 06 15:18:46 rasp mitkdc[4438]:   /usr/sbin/krb5kdc: Stash file (null) uses DEPRECATED enctype !
Jul 06 15:18:46 rasp mitkdc[4438]: [2021/07/06 15:18:46.585427,  0] ../../lib/util/util_runcmd.c:352(samba_runcmd_io_handler)
Jul 06 15:18:46 rasp mitkdc[4438]:   /usr/sbin/krb5kdc: krb5kdc: starting...
Jul 06 15:18:46 rasp winbindd[4449]: [2021/07/06 15:18:46.665042,  0] ../../source3/winbindd/winbindd_cache.c:3204(initialize_winbindd_cache)
Jul 06 15:18:46 rasp winbindd[4449]:   initialize_winbindd_cache: clearing cache and re-creating with version number 2
Jul 06 15:18:46 rasp winbindd[4449]: [2021/07/06 15:18:46.677092,  0] ../../lib/util/become_daemon.c:152(daemon_ready)
Jul 06 15:18:46 rasp winbindd[4449]:   daemon_ready: daemon 'winbindd' finished starting up and ready to serve connections

AFAICS error 110 should be related to a time out. (named not ready?)
the samba-ad-dc.service is

rasp:~ # cat /etc/systemd/system/multi*/samba-ad-dc.service
[Unit]
Description=Samba AD Daemon
Documentation=man:samba(8) man:samba(7) man:smb.conf(5)
Wants=network-online.target nss-user-lookup.target
After=network.target network-online.target
Before=nss-user-lookup.target

[Service]
Type=notify
PIDFile=/run/samba/samba.pid
LimitNOFILE=16384
EnvironmentFile=-/etc/sysconfig/samba
Environment=KRB5CCNAME=/run/samba/krb5cc_samba
ExecStartPre=/usr/share/samba/update-apparmor-samba-profile
ExecStart=/usr/sbin/samba --foreground --no-process-group $SAMBAOPTIONS
ExecReload=/bin/kill -HUP $MAINPID


[Install]
WantedBy=multi-user.target
rasp:~ # 

DNS (named) service is mandatory for samba-ad-dc. Should named.service not be included in the [Unit] “after=” line?.
Should I open a bug report for this?

Another question: Is it normal that after a reboot in the status, I see lines related to smbd but not after a restart of samba-ad-dc?

Many thanks in advance
Philippe