Does a baby control everything?
If your baby has completed a mental leap, it means that he has come to terms with his new perceptual ability. He is no longer crying, cranky and clingy. But that does not mean that he can do everything or has all the skills that this new kind of perception potentially has given him. Basically his brain is now capable of developing a whole set of new skills, but your baby has to try them out and practice before he can fully control them. This does not happen by itself. Your baby will learn by experience, learn by mistakes, and learn by trial and error.
This exercise takes a lot of time. Your baby will master some skills right after a leap, but other skills will have to wait or take more time. And babies differ regarding their preferences and what skills they develop quickly after a leap.