The darkbot software implements a feature to catch exceptions like
a segmentation fault, and then exits properly the software with
a non zero code.
The quit message on IRC explains the intercepted signal:
Quit: Caught SIG_SEGV! Aborting connection. Uptime: 893 hours, 10 mins
In such case, we want systemd to immediately restart the service,
to improve service availability. This is not the default behavior,
as systemd prefers to mark unit status as failed.
Reference: https://www.freedesktop.org/software/systemd/man/systemd.service.html#Restart=
Fixes T1213.