Situation as described on IRC: net-dns/nsd-3.2.6 is installed, a binary package for it is available, it is unmasked via package.keywords. The overlay was updated, version 3.2.6 was dropped, 3.2.7 added. This version is keyword masked for my arch. When updating world (--newuse or not), portage will want to reinstall the net-dns/nsd-3.2.6 binary package. Reason is probably that the new 3.2.7 version triggered an update, but later 3.2.6 was selected as the only installable option because of the keyword mask of 3.2.7. Reproducible: Always
This is fixed in git: http://git.overlays.gentoo.org/gitweb/?p=proj/portage.git;a=commit;h=e4bcbdace3e0c28c39fdc9a92da38b21611638bf
We can count this bug as a regression since the different_version code, that was remove in the following commit, guarded against this type of problem: http://git.overlays.gentoo.org/gitweb/?p=proj/portage.git;a=commit;h=2553847b6b7795719ee7b4439f34182dcd66fcae
This is fixed in 2.1.9.40 and 2.2.0_alpha24.