Bind9 fails to start automatically

After rebooting master dc, bind9 will not start automatically.
Error posted in systemctl status bind9:

loading configuration: shutting down exiting (due to fatal error)
…/…/…/bin/named/client.c:3516: unexpected error: isc_socket_accept () failed: shutting down
bind9.service: Main process exited, code=exited, status=1/FAILURE
Failed to start BIND Domain Name Server with samba4 backend.
samba_dlz: shutting down

If I manually start the service, everything loads correctly. Seems bind9 starting too quickly before samba4. Is there anything I can do to fix the issue?

With Regards,

Russ

After running some tests, I found that replacing in the systemd bind9 service file {/etc/systemd/system/bind9.service.d/10-configure-backend.conf) the entry for Type=simple to Type=oneshot under [Service], the problem goes away! This file is auto-generated by /etc/univention/templates/files/etc/systemd/system/bind9.service.d/10-configure-backend.conf. So there seenms to be a problem with the template.