A couple of days for now, 12 CURRENT (Revision: 338541) doesn't build packages anymore when source tree invoked via "make packages". The packaging process dies somewhere with *** [create-world-package-runtime] Error code 70 and some lines above this messages there is [...] pkg: duplicate directory listing: /root, ignoring pkg: Plist error, @config /root/.cshrc: not a regular file pkg: Plist error, @config /root/.profile: not a regular file [...]
Please look at that thread https://lists.freebsd.org/pipermail/freebsd-pkgbase/2018-September/000383.html
This is fixed in pkg-devel.