Okay, the it is the "luck of the draw". Keep in mind that this model has its own bias, so the less "evidence" it has, the more it will try to pull you to a state you many not want.

If for some reasons in your logs this happens at the mark of the fourth post, that means that the context you are giving it is 1/4 likely to link your contents to a story you don't want. Simply erase that message and reroll until you get something that you like. That will reduce the random chance of derailing as you progress.

Keep in mind that this all depends on how much allow the model to modify your run and how many "tools" you give it. A nice character cannot exist in a "violent world". And since the bias is elsewhere, if you allow an "evil" character and you try to "convert it", unless you do some heavy workarounds, the model will resist as it will not make sense in the context.

The opposite is true, after the last updates, if your story is too nice oriented, you won't be able to turn them "organically" into a violent run unless you explicit add the violence. And even then, there are chances of the model returning you to sunshine and rainbows.

Maybe you are trying to go for a realistic story where there is a balance between the two, the problem is that the model will refuse to do this and just stick with the run at hand, so the best approach for this is to actually have the story in mind and only let the model fill the gaps via all the "What happens next" and reminder boxes.

Hope that helps, if you have a more particular problem, do ask, there are a million of workarounds with the current model, and since we were forced to it, best we can do is adapt.