Your example color I would call sort of gold. I get that if there is a section which has some new items which I haven't read. For example, I stopped following the captions in the games category, so Games always has this gold indicator.
My archive indicators are gray. When I go into that, all of the ones in it are gray unless there is a category with new posts, and then that one is blue.
Anyway, it's nice to know it isn't just something with my set up.