The Resource Harvesting sovereign choice says that it causes goody crates to spawn near crystal mines, iron mines, and other resources.

In a game I played as the Tinkerer, they spawned around crystal mines, iron mines, clay pits, and pastures.  There were so many I had to use two scouts to grab them all.  They kept spawning with a declining frequency until just one crystal and one iron mine were spawning one per turn, which was the way it was until the end of the game.

In a game I played as the Wizard, they spawned only around one iron mine.  That mine and only that mine generated them until the end of the game.

In my current game as the Guardian, no chests have spawned at all.  I haven't finished the game yet, but it's been more than 60 turns since I selected that choice from the tree.

So is this broken for some sovereigns, or is it just using a really bad random number generator?

Edit: I guess I should note that this is on SK: Rivals.