The J/P dimension is basically the Big 5 dimension 'Conscientiousness' added to Jungian Psychological Types by Isabel Myers. Now this by itself is not an error.

The error is that Myers assumed that this dimension was the same as Jung's Rational/irrational dichotomy. But it isn't, and in order to make the system work, she decided the J/P dimension must reflect the extraverted function (in introverts the 2nd function). We all know the results.

As the referred article mentions, e.g. both ISTP´s and ENFP´s can be very tidy people. This is confirmed by Cognitive Psychology, that teaches us that extreme low or high conscientiousness can be ´reprogrammed´. It is more of a learned behavior rather than an inborn personality trait.