This ebuild has KEYWORD="-*" and doesn't emerge with "missing keyword" error. Is this a typo or is this a new way of masking a package ? over using /usr/portage/profile/package.mask ? I have severe issues with 5.0.18 as it crashes consistently on a Grant select...
This is not a bug. You need to 'put dev-db/mysql -*' into /etc/portage/package.keywords to emerge such ebuild. Will be keyworded when tested/ready.