When trying to figure out why firejail was causing apparmor to fail to reload, I found firejail profile includes the files /etc/apparmor.d/abstractions/dbus-session-strict and /etc/apparmor.d/abstractions/dbus-strict installed by the package apparmor.

These two files contain a reference to the variable @{run} but the variable is not defined and cause apparmor to fail to reload the profiles.