HoMM3 HD is a mod (add-on) for the game Heroes of Might and Magic 3.

I also experienced settings being reset in one of the latest versions. The solution was simple: configure the map, select the castles, return to the map configuration, choose the desired settings, and start the generation without switching to the castle selection. The problem only occurred during the first generation; in the second and subsequent attempts, you could start the generation from the castle selection window.