Comment 5 for bug 2057937

> Correct, apparmor is not installed and never was.

Interesting, because it seems to be enabled. The systemd service would not have failed to load the apparmor profile if apparmor were disabled[1]:

  This setting has no effect if AppArmor is not enabled.

Do you have the /sys/kernel/security/apparmor/profiles file, and does it have a list of loaded profiles by any chance?

In any case, the fix here seems to be to change the AppArmorProfile=ubuntu_pro_apt_news line to AppArmorProfile=-ubuntu_pro_apt_news in the apt_news.service unit file, but I'm trying to understand the situation a bit better before doing that. I didn't think apparmor could be enabled without the apparmor package installed on the system.

1. https://www.freedesktop.org/software/systemd/man/latest/systemd.exec.html#AppArmorProfile=