I think the original intention for the OP was for Colapinto to be at Alpine from the start of the careers and also in the Grand Prix mode too, yeah.
It was just coincidence that in your game Franco joined the actual team he joined in real life. Although one that would happen more often than not as although he's shonky in real life, the game gives him VASTLY overrated stats and encourages his promotion to the grid and as Alpine are a backmarker team, he'd join them more often than he would a Red Bull or McLaren.
