Cast & Crew missing with custom agent

Hm, I’ve just got mine up and running by modifying the example tmdb provider, and it’s functioning well.. but the new experience apps still don’t have Cast & Crew listed.
Is it because they’re manually built cast, rather than being pulled from Plex’s sources?

        const roles: Person[] = result.cast.map(member => {
            const url = actorUrlMap[member.actor.id] || member.actor.url;
            return {
                tag: member.actor.name,
                role: member.character.name,
                thumb: url || "", // Default placeholder if no image
            };
        });
...
...

        const metadata: MovieMetadata = {
            ...
            Role: roles.length > 0 ? roles : undefined,
            ...
        }