Just as Valamas asked about Technologies, why is the boost bar below Mercenaries pink while Civil Service and Medieval Faires are gray? I have boosted all three Civics, and I haven't researched any of them. My only guess would be that the boost to Mercenaries came from a Goody Hut except I definitely have more than eight land combat units.
Note: In the screenshot, I haven't chosen my next Civic to research yet. Going back into the game and choosing one (and switching around) has no effect on any of the bars.