B team problem

I created a B team for Liverpool to develop youth with the pre-game editor. Set up the same way as Real Madrid and Real Castilla in theory, with players move freely enabled and so on. Has always worked on previous FMs, players could move between teams as I pleased able to play any game. In FM18 however, whenever I move a player down to the B team, they are noted as 'unavailable' to play any games? I am the manager of both the parent and b team club. Even in advanced rules editor there are no restrictions on b clubs.

Is this an error or am I missing something?