The spawned English Galleons also frequently change roles to ASSAULT_SEA, stranding the spawned Settler and precluding further spawns (if I understand the system, iColonistsAlreadyGiven is active until Settler is consumed?) . Actually, this is probably what's happening rather than the Colonists now spawning at all as stated above. What's unclear is what threshold for ASSAULT_SEA transports England AI wants to meet before permitting a SETTLER_SEA, but it's quite a few, though as youre certainly aware this preference is subject to conditions, mainly war/peace.