Carolean seems to have a 0.8x melee multiplier penalty against rifle infantry (skirmisher type units) but not against foot archers which are also supposed to be counters to caroleans. Foot archers and rifle infantry fulfills the same role and should be treated rather equally in this case. Carolean should get penalty against both, to prevent swedes player to abuse the melee charge against their supposed counters.
Im not sure if this is a bug or intended, but skirmishers get advantage over archers vs caroleans.