core-kit + Gentoo overlay = package masking weirdness

[mrhnhrm]

Hi, and thanks for taking a look.

So, here I have a system in which I installed the Gentoo overlay via Layman. Now every time emerge is invoked, it prints a warning

!!! Repository name or alias 'gentoo', defined for repository 'core-kit', overrides existing alias or repository.

This alone is a minor inconvenience, but there is something else. Usually, I install overlays for one or few very specific packages or versions. So, after installing an overlay, I would mask all the packages in it (echo '*/*::gentoo' >> /etc/portage/package.mask), and then unmask what I need in /etc/portage/package.unmask (which I think is the common practice). And here's the thing: if any package belonging to the Funtoo core-kit is (planned to be) merged without specifying exact version, and there happens to be a newer version in the the Gentoo overlay, then the latter will be chosen for merging despite that particular package from the Gentoo overlay is not explicitly unmasked. This strange behaviour happens only with packages that belong to the Funtoo core-kit.

Any suggestions about how to settle the feud between the core-kit and the Gentoo, please?