I think it's got something to do with trade rights you give to a merchant republic that doesn't own a CoT.
That, or you don't have cores in there and don't accept their culture/religion. When the locals hate your guts, they want to trade on the other side of the unknown world, just to be painful.
That, or you don't have cores in there and don't accept their culture/religion. When the locals hate your guts, they want to trade on the other side of the unknown world, just to be painful.