When you stockpile food into your settlement, there should be an option to determine the minimum amount of food needed in that settlement before exporting a surplus is allowed. AI settlements would also need this option and change their settings based on their prosperity/food income, as they are always starving.
For example, I bought a massive amount of food for my settlement. Within 5 minutes, about 100 caravans arrived and bought all of that food leaving none left. Sure, the settlement made a fortune, but it left that settlement with another food shortage. The end result is that the prosperity, garrison, and militia all decline.
In my opinion, this is a game breaking bug, as it becomes impossible to have a stable kingdom because you constantly lose troops which in turn makes your settlements constantly retaken.
For example, I bought a massive amount of food for my settlement. Within 5 minutes, about 100 caravans arrived and bought all of that food leaving none left. Sure, the settlement made a fortune, but it left that settlement with another food shortage. The end result is that the prosperity, garrison, and militia all decline.
In my opinion, this is a game breaking bug, as it becomes impossible to have a stable kingdom because you constantly lose troops which in turn makes your settlements constantly retaken.

