Oh, it seems to happen when there's a version mismatch between libnetplan0 and netplan.io. And unattended-upgrade normally only upgrade one package at the time:
Log started: 2021-04-07 06:58:28
Preparing to unpack .../libnetplan0_0.102-0ubuntu1~20.04.1_arm64.deb ...
Unpacking libnetplan0:arm64 (0.102-0ubuntu1~20.04.1) over (0.101-0ubuntu3~20.04.2) ...
Setting up libnetplan0:arm64 (0.102-0ubuntu1~20.04.1) ...
Processing triggers for libc-bin (2.31-0ubuntu9.2) ...
Log ended: 2021-04-07 06:58:34
Apr 7 06:58:38 smart-gold-dragonfly-02 systemd[2226429]: /usr/lib/systemd/system-generators/netplan terminated by signal SEGV.
Log started: 2021-04-07 06:59:00
Preparing to unpack .../netplan.io_0.102-0ubuntu1~20.04.1_arm64.deb ...
Unpacking netplan.io (0.102-0ubuntu1~20.04.1) over (0.101-0ubuntu3~20.04.2) ...
Setting up netplan.io (0.102-0ubuntu1~20.04.1) ...
Processing triggers for man-db (2.9.1-1) ...
Processing triggers for dbus (1.12.16-2ubuntu2.1) ...
Log ended: 2021-04-07 06:59:05
Oh, it seems to happen when there's a version mismatch between libnetplan0 and netplan.io. And unattended-upgrade normally only upgrade one package at the time:
Log started: 2021-04-07 06:58:28 _0.102- 0ubuntu1~ 20.04.1_ arm64.deb ... 0ubuntu1~ 20.04.1) over (0.101- 0ubuntu3~ 20.04.2) ... 0ubuntu1~ 20.04.1) ...
Preparing to unpack .../libnetplan0
Unpacking libnetplan0:arm64 (0.102-
Setting up libnetplan0:arm64 (0.102-
Processing triggers for libc-bin (2.31-0ubuntu9.2) ...
Log ended: 2021-04-07 06:58:34
Apr 7 06:58:38 smart-gold- dragonfly- 02 systemd[2226429]: /usr/lib/ systemd/ system- generators/ netplan terminated by signal SEGV.
Log started: 2021-04-07 06:59:00 io_0.102- 0ubuntu1~ 20.04.1_ arm64.deb ... 0ubuntu1~ 20.04.1) over (0.101- 0ubuntu3~ 20.04.2) ... 0ubuntu1~ 20.04.1) ... 2ubuntu2. 1) ...
Preparing to unpack .../netplan.
Unpacking netplan.io (0.102-
Setting up netplan.io (0.102-
Processing triggers for man-db (2.9.1-1) ...
Processing triggers for dbus (1.12.16-
Log ended: 2021-04-07 06:59:05