I can easily reproduce this with
rm /var/lib/update-notifier/updates-available; /usr/lib/update-notifier/update-motd-updates-available & /usr/lib/update-notifier/update-motd-updates-available
I can easily reproduce this with
rm /var/lib/ update- notifier/ updates- available; /usr/lib/ update- notifier/ update- motd-updates- available & /usr/lib/ update- notifier/ update- motd-updates- available