Samba server quits with sigterm overnight

Hello,
i experience the following strange problem with Samba Server Version 4.10.1-Univention
Installed Univention is 4.4-3 errata438, upgraded from 4.3
The Problem exists after the upgrade

Somehow, the samba server dies in a strange way overnight:

[2020/02/08 09:12:22.693179, 1, pid=2162] …/…/source4/dsdb/kcc/garbage_collect_tombstones.c:68(garbage_collect_tombstones_part)
Doing a full scan on CN=Configuration,DC=asdf,DC=intranet and looking for deleted objects
[2020/02/08 09:12:22.759257, 1, pid=2162] …/…/source4/dsdb/kcc/garbage_collect_tombstones.c:68(garbage_collect_tombstones_part)
Doing a full scan on DC=asdf,DC=intranet and looking for deleted objects
[2020/02/08 20:44:18.085558, 0, pid=2155] …/…/source4/smbd/process_standard.c:84(sigterm_signal_handler)
[2020/02/08 20:44:18.085619, 0, pid=2163] …/…/source4/smbd/process_standard.c:84(sigterm_signal_handler)
[2020/02/08 20:44:18.164698, 0, pid=2158] …/…/source4/smbd/process_standard.c:84(sigterm_signal_handler)
sigterm_signal_handler: Exiting pid 2163 on SIGTERM
sigterm_signal_handler: Exiting pid 2155 on SIGTERM
sigterm_signal_handler: Exiting pid 2158 on SIGTERM
[2020/02/08 20:44:18.254025, 0, pid=2152] …/…/source4/smbd/process_standard.c:84(sigterm_signal_handler)
sigterm_signal_handler: Exiting pid 2152 on SIGTERM
[2020/02/08 20:44:18.158038, 0, pid=2153] …/…/source4/smbd/process_standard.c:84(sigterm_signal_handler)
sigterm_signal_handler: Exiting pid 2153 on SIGTERM
[2020/02/08 20:44:18.200382, 0, pid=10174] …/…/source4/smbd/process_standard.c:84(sigterm_signal_handler)
sigterm_signal_handler: Exiting pid 10174 on SIGTERM
[2020/02/08 20:44:18.943078, 0, pid=2162] …/…/source4/smbd/process_standard.c:84(sigterm_signal_handler)
sigterm_signal_handler: Exiting pid 2162 on SIGTERM
[2020/02/08 20:44:18.953554, 0, pid=2160] …/…/source4/smbd/process_standard.c:84(sigterm_signal_handler)
[2020/02/08 20:44:18.937775, 0, pid=2159] …/…/source4/smbd/process_standard.c:84(sigterm_signal_handler)
sigterm_signal_handler: Exiting pid 2159 on SIGTERM
[2020/02/08 20:44:18.872159, 0, pid=2156] …/…/source4/smbd/process_standard.c:84(sigterm_signal_handler)
sigterm_signal_handler: Exiting pid 2156 on SIGTERM
sigterm_signal_handler: Exiting pid 2160 on SIGTERM
[2020/02/08 20:44:18.951977, 0, pid=2161] …/…/source4/smbd/process_standard.c:84(sigterm_signal_handler)
sigterm_signal_handler: Exiting pid 2161 on SIGTERM
[2020/02/08 20:44:19.058995, 0, pid=2151] …/…/source4/smbd/process_standard.c:84(sigterm_signal_handler)
sigterm_signal_handler: Exiting pid 2151 on SIGTERM
[2020/02/08 20:44:23.479042, 0, pid=20289] …/…/source4/smbd/server.c:587(binary_smbd_main)
samba version 4.10.1-Univention started.
Copyright Andrew Tridgell and the Samba Team 1992-2019
[2020/02/08 20:44:27.464356, 0, pid=20294] …/…/source4/smbd/server.c:773(binary_smbd_main)
binary_smbd_main: samba: using ‘standard’ process model
[2020/02/08 20:44:27.481690, 0, pid=20294] …/…/lib/util/become_daemon.c:136(daemon_ready)
daemon_ready: daemon ‘samba’ finished starting up and ready to serve connections
[2020/02/08 20:44:42.508098, 1, pid=20424] …/…/source4/dsdb/kcc/garbage_collect_tombstones.c:68(garbage_collect_tombstones_part)
Doing a full scan on DC=ForestDnsZones,DC=asdf,DC=intranet and looking for deleted objects
[2020/02/08 20:44:42.509476, 1, pid=20424] …/…/source4/dsdb/kcc/garbage_collect_tombstones.c:68(garbage_collect_tombstones_part)
Doing a full scan on DC=DomainDnsZones,DC=asdf,DC=intranet and looking for deleted objects

After that, in the morning, the shares are not accessible anymore from both Windows 7 and windows 10 Clients.

The samba server itself may run in a way, smbclient -L localhost gives me for example the servicees.
It only works again, if i do a /etc/init.d/samba restart

At the moment i installed a cron job which does this restart command ad 6:30 am.
What else can i do?

thanks,
Chris.

I updated this System to latest Univention 4.4-… This never happened again then. Was a strange error, though.