Where I personally experienced the learning, more of a calibration really, is use of AP for parallel parking. Mine did not work initially but after a few weeks of use spots where it did not work previously work perfectly now. I found the auto steering to work well in most conditions other than early morning or late afternoon sun where there tens to be glare over the lane markings.
"Calibration" is the right term for activating the self-parking feature. On a road trip in early November, I stopped in at a service center a couple of weeks after getting the Autopilot update and had a discussion with one of the techs about my experiences with AP. I mentioned that I'd never gotten the self-parking feature to trigger and he said that the ultrasonics had to be calibrated before it would work. How? By giving the car experience 'seeing' curbs from close range. So I went out in the SC's parking lot and drove around for a few minutes at various distances from the curbs, on both sides of the car, noting that the proximity indications on the instrument cluster for the side sensors became more frequent and more consistent as I continued. Then I went looking for a parallel parking opportunity and, lo and behold, after a few false starts it began offering me the big boxed 'P' indication. I gave the car several shots at parallel parking and it performed flawlessly, including putting me into one parking spot so tight that it took me a couple of tries to get the car back out again.