I think it’s probably quite straight forward; the AI will look predominately at CA, if there’s a great prospect with 120 and 200 PA, they possibly don’t see PA as something that’s worth developing by playing the player. They’ll also go out and buy a striker with 150 ca and 150 pa (finished article) and this player will block the young player. It’s the simplest explanation.
A human will be more inclined to play Moukoko, knowing that there’s a chance he’ll be excellent, and happily suck up taking the CA hit in the short term.
It’s no doubt a tricky fix but a player with a high PA should be played more, ignoring the low CA whilst they develop.