My 19 y.o won't increase the point when learning a new role

[molouqman]

I never have any problem with learning a new role on my youngster, but when i try to learn a new role for this player it won't increase even 1 point. And my player is still 19 years old. Is it because i have already power train him before learning the new role ? My drill was still same, i'm using full slot Fast Counter-Attacks and have no problem on my previous youngster.