i'm not sure of it, but IMO anacron should provide virtual/cron and additionaly should be blocked by other crons
Created attachment 32024 [details]
here's my proposal for fix described problem
according to the HOMEPAGE anacron isnt really a cron replacement, just a supplement ... plus the ebuild itself RDEPEND's on virtual/cron ...
some people use anacron in conjunction with a regular cron daemon
adding this patch would prevent them from doing so