It's now been suggested to me that my issue was related to saving and re-loading a game within the same session, as I have a dirty cheater's habit of reloading a game after dying if I enter a quest location to complete it, and find it is populated with lethal bulls*** I couldn't have possibly handled. Or if I accidentally click on the wrong square during a tac battle and blunder my way into a loss because of the interface. Or if my sovereign gets ridiculously killed by a bear cub that mauls me for 5 consecutive hits.  Or if I discover that the creature I had been handling just fine in .77 now spam's Titans Breath turn after turn.  Or if I accidentally forget to queue a building to be built for several turns, or build on the wrong square.  Or if I get a hangnail.

The point is, if you do any of that, you probably shouldn't, or it may corrupt your game in progress until the issue is fixed.