Discrepancy in lore (spoilers)

[Brightamethyst]

Eorzea isSecond, the Empire's wide swathe of provincial territories is itself a handicap: because it generally mistreats conquered peoples, the Empire needs to keep its legions garrisoned in the provinces to discourage and quash rebellions. That means no matter how powerful its military might be it can't commit all its forces to an offensive without taking a huge risk.

Which was the entire reason SB worked. Stirring up trouble on two fronts, distracting Zenos and making him further split his forces.