[AI teams can't register home-grown players from the league nation]

I have encountered this issue in polish ekstraklasa, after secons season started (summer 2021). Teams play only with foreigners/young players. 

I have checked other leagues and I can't see similar issues.

I have started my save 25th Nov, so i guess it's not a beta issue.

I have attached a save. "WisłaKrakóws02_squad_registration_issue.fm"

[AI squad registration issues.]

In my save AI can't register current players from club. Only registrated players was new transfers.