The suffixes on mount insignia give a predictable set of stats. However, in the case of the Enlightened Insignia of Skill, the insignia has Action Point Gain instead of the expected Combat Advantage Bonus. This error occurs at all quality levels. This is not merely a tooltip error, I tested equipping the insignia.
Enlightened Insignia of Skill with (incorrect) Action Point Gain: Barbed Insignia of Skill with Combat Advantage Bonus: Crescent Insignia of Skill with Combat Advantage Bonus: