Commit c41c56e3 "version bump; clean old" removed version 2.4.20 of app-emulation/vice which was the stable version (at least for some platforms) and replaced it with 2.4.22 which naturally is not stable for any platform. I believe this was a mistake and it was the older 2.4 version that was intended to be removed instead.
whoops. forgot that was marked stable. should be back now.