When unlocking new classes, a silhouette slowly fills up to show your progress:
I've noticed each character has an affinity for each class, which determines why it sometimes fills up slowly as opposed to other characters, but why does it seem to not fill up at all for a while? I don't seem to notice the bar filling up until I'm at least rank 5 in that class (paired with the Hero for each class as well, for bonus gains). Is there a time where it doesn't apply to other characters, or how does this mechanic work?