I'm unsure about wether this is a bug or not...
Yesterday I genned a world and got interested in one special goblin empire, alone to the west, and their 600-year-old leader Osnun.
At the end of the gen she murdered some goblins after 500 years of nothing.
I wanted to know if I could find out why. So I generated the same world, using the same seeds for world, names and history after moving away this world (it seems like it won't generate 2 identical regions in the same "save" file).
I checked the world : the geography was the same, the territories were the same. This hydra died then, killed by the same guy.
The only differences I had in the parameters were that I didn't cull unimportant things and that I let it go until 1000 instead of 600.
Problems came here. Osnun murdered her husband 2 years before the latter was supposed to be killed by an hydra, in an attempt to save Osnun's life.
Also, she murdered different people, thus causing different goblins to live and die.
It means the goblins murder are independant of the seed. This way, the same seed won't always generate the same history. Goblins, by randomizing their murders, have found a way to escape the matrix.
I'm not sure wether it's a feature or a bug, but I must say I don't like it. I wanted to let the game be generated until a few centuries later and see how things were going, now those goblins ruined it.