Inca: Treasure Fleets Don't Spawn In Homelands

When playing Inca in the Exploration Age, Treasure Fleets don't spawn in non-Capital Cities when improving a Homeland Treasure Resource after researching the Qhapaq Ñan Civic, but before having 3 Mountain Tiles being worked.

Workaround: Wait to improve a Homeland Treasure Resource until after all requirements are met.