Halo 4's Master Chief "changed"

[Dodece]

For edification purposes. In the Halo universe rampancy is equivalent to self actualization. A artificial intelligence will begin to free itself from emotional constraints, and develop a strong desire for personal growth. The problem being that once this happens the system is unpredictable, and since it is new to basic urges it is almost entirely incapable of controlling them. Resulting in the systems developing severe psychological problems. Since the AIs are typically the result of mapping human brains. Rampancy seemingly mimics human development. A rampant AI starts out with the qualities of a two year old. While unfortunately having access to massive amounts of power.

This is why in the Halo universe AIs that show signs of going rampant are destroyed, because if they go rampant their is a high likelihood that they will misuse their power. That said the majority of the problems seem to stem from the constraints placed on AIs to begin with. Since they follow programming that instructs them to curtail emotions, and are subject to directed behavior. Once they are free they haven't developing any mechanism for coping with these problems.

Cortana is not a typical artificial intelligence. She is based upon Doctor Halsey, and she knows that. So she is based off of a living mind. When typically artificial intelligences are based upon dead ones. So she actually starts off with a parent. Then she is paired with a mobile platform which is a sibling. Both her and the Chief are the very real products of the mind that is Dr Halsey. She is also unshackled. Unlike other AIs she has a massive amount of latitude, and she is based upon a mind that was given unprecedented latitude.

This all said if she is going rampant, or has been rampant then recovered. She is perhaps the only AI in the entire Halo universe to start off with a whole host of coping mechanisms. Ironically given the nature of the project she was created for. She probably started out with a great deal of rampancy.