I'm having an issue where, whenever I reroll on any of the maps in this map pack, the rivers don't load in. This only occurs when I restart a game, never when I first load it. I checked my mods and I have no mods installed that affect terrain generation.
On a related note: There problems where some rivers that are floodplains don't flood. I've noticed so far only on the Tigris and Euphrates rivers in the Play Europe Again map.