After hiring a set of soldiers, I tried to hire some more a month later in game, the list for the soldiers was blank, and I could not hire new soldiers.
I would be able to load these saves occasionally from inside the loaded game, but after I CTD and have to reload, it would CTD while loading the save I had been able to load before.
When I land on the new tile sets, there are plenty of invisible npcs, and when they are killed there is a CTD, this problem seems quite similar to the reload problem when the invisible aliens who crash out the game when they are killed.
Game starts in September game time, when the month switches and I reload my saves from October game time and the game crashes, does not crash when I reload the September saves.