When a Fleet Skill Boost is activated, it lists both space and ground traits as buffed. However, if the boost is activated on the ground, the boost fails to apply when in space. Meaning the buff icon isn't present and when looking at the skill based stats page, the bonus isn't applied. If the boost is activated in space the opposite happens and the boost doesn't apply when you are on the ground. Given that the boost states that it buffs both space and ground I suspect this may be a bug.