This bug was fixed in the package console-setup - 1.178ubuntu4
--------------- console-setup (1.178ubuntu4) cosmic; urgency=medium
* debian/console-setup-udeb.postinst: Guard the dpkg call in the postinst, so it isn't attempted in the debian-installer environment (LP: #1782835)
-- Adam Conrad <email address hidden> Fri, 20 Jul 2018 14:22:45 -0600
This bug was fixed in the package console-setup - 1.178ubuntu4
---------------
console-setup (1.178ubuntu4) cosmic; urgency=medium
* debian/ console- setup-udeb. postinst: Guard the dpkg call in the postinst,
so it isn't attempted in the debian-installer environment (LP: #1782835)
-- Adam Conrad <email address hidden> Fri, 20 Jul 2018 14:22:45 -0600