OPi4: hostapd does not run as service (but starting from CLI is fine)

Using Armbian bionic (Ubuntu 18.04) on a Orange PI4, hostapd does not run as service. Neither at startup, nor when stopped and restarted manually.

However, starting it from command line works fine?

Logfiles (syslog, journalctl) do not show anything helpful.

root@IA216:~# service hostapd status
● hostapd.service - LSB: Advanced IEEE 802.11 management daemon
   Loaded: loaded (/etc/init.d/hostapd; generated)
   Active: active (exited) since Sun 2020-10-18 12:54:28 CEST; 8h ago
     Docs: man:systemd-sysv-generator(8)
  Process: 31481 ExecStop=/etc/init.d/hostapd stop (code=exited, status=0/SUCCESS)
  Process: 31542 ExecStart=/etc/init.d/hostapd start (code=exited, status=0/SUCCESS)

Oct 18 12:54:28 IA216 systemd[1]: Starting LSB: Advanced IEEE 802.11 management daemon...
Oct 18 12:54:28 IA216 systemd[1]: Started LSB: Advanced IEEE 802.11 management daemon.

You see, hostapd just exits "successfully" after start. Same happens, if I `restart` (or `start` / `stop`) hostapd:

root@IA216:~# service hostapd restart
root@IA216:~# service hostapd status 
● hostapd.service - LSB: Advanced IEEE 802.11 management daemon
   Loaded: loaded (/etc/init.d/hostapd; generated)
   Active: active (exited) since Sun 2020-10-18 21:35:53 CEST; 3s ago
     Docs: man:systemd-sysv-generator(8)
  Process: 26368 ExecStop=/etc/init.d/hostapd stop (code=exited, status=0/SUCCESS)
  Process: 26369 ExecStart=/etc/init.d/hostapd start (code=exited, status=0/SUCCESS)

Oct 18 21:35:53 IA216 systemd[1]: Starting LSB: Advanced IEEE 802.11 management daemon...
Oct 18 21:35:53 IA216 systemd[1]: Started LSB: Advanced IEEE 802.11 management daemon.
root@IA216:~# journalctl -n
-- Logs begin at Sun 2020-10-18 01:24:00 CEST, end at Sun 2020-10-18 21:35:59 CEST. --
[...]
Oct 18 21:35:53 IA216 systemd[1]: Stopping LSB: Advanced IEEE 802.11 management daemon...
Oct 18 21:35:53 IA216 systemd[1]: Stopped LSB: Advanced IEEE 802.11 management daemon.
Oct 18 21:35:53 IA216 systemd[1]: Starting LSB: Advanced IEEE 802.11 management daemon...
Oct 18 21:35:53 IA216 systemd[1]: Started LSB: Advanced IEEE 802.11 management daemon.

If I start with

/usr/sbin/hostapd -dd -B -P /run/hostapd.pid /etc/hostapd.conf

everything is fine?