I read an MBTI description that said don't hook up with INTPs because they act like a J and slowly as you get to know them they return to their P and became lazy and messy.
Well of course it's true that people act a certain way until they are comfortable around other people, but is that 'certain way' a projection of the Id? I think it would sort of be like "Haha you think this is how I really am, but it's not, while I fool you into letting your guard down". Maybe in an attempt to protect the PoLR?
On one occasion I've noticed a distinct difference in behavior. An ESTP, new to the group, became an exact lookalike of an ESTJ, . She was all gung ho about work and everything and was really straight to the point. Once, integrated however, the began to show.