I'd dispute that. I just started playing yesterday after waiting for the personalities and I definitely had situations with the "free" personality (Ishmashell for example, I wanted to toss him back and so did the 2nd character) where the AI decided the same way I did.
well it could be interpreted that it looks at what your active's current trait is (not necessarily decision)
since you probably didnt have altruistic or egotistical at that stage since its like early in the game, then it just chose randomly
but now that you gained the egotistical, next time he will go for altruistic
