I had no notion about this before my game crashed yesterday (it tends to do that every now and then) and I lost over 3 hours of gameplay 'cause the game never saved on its own once I saved manually (maybe it didn't do before either, can't tell now, can I?). And one can't qicksave (you get a message that quicksave is restricted in Trial of Iron) and the manual save (from the menu) will always send me back to the main menu.
I don't know but it seems like a very bad design anyway that I can not save my progress without quitting the session - in a game that won't autosave in a particular game mode. Especially if said game keeps crashing (at least for as long as there is the problem with "access restrictions").
Since one's not supposed to reverse their decisions (hence only one save) I thought the game might at least autosave whenever I set foot in another region (it seems to work that way in a non-'Trial of Iron' session).