Not sure this is a bug, however I compiled bind on one machines, created a binpkg and now trying to install it on an other machine, this is printed (the installation succeeds):
machine1# emerge -av1b net-dns/bind
builds fine, pkg is created
machine2# emerge -av1k net-dns/bind
>>> Original instance of package unmerged safely.
/bin/tmpfiles: line 506: /var/tmp/portage/net-dns/bind-9.16.12/files/named
.conf: No such file or directory /var/tmp/portage/net-dns/bind-9.16.12/temp/environment: line 2662: [: missing `]'
* You can edit /etc/conf.d/named to customize named settings
Looking at the ebuild it sems to be this piece:
Anyways, /usr/lib/tmpfiles.d/named.conf is present on both machines.