Database contains embedded objects, but MongoRepository returns empty List

@Document("scenarios")
public class Scenario {
    @Id
    private String id;
    @Indexed(unique = true)
    private String name;
    private String description;
    @JsonSerialize(using = PlatformSerializer.class)
    private final List<Platform> platforms;
// getters and setters not shown
public class Platform {
    private final PlatformData platformData;
    @JsonSerialize(using = RowSerializer.class)
    private final List<Row> rows;
// getters and setters not shown

The scenarios collection contains the embedded Platform objects. When I get the Scenario object from the database using the ScenarioRepository object shown below, the name and description values are correct. However, the platforms List is empty. I seem to recall that containers require an annotation. Though the Scenario object was saved to the database just fine. What the hell am I missing? Thanks!

@Repository
public interface ScenarioRepository extends MongoRepository<Scenario, String> {
    Scenario findByName(String name);
}
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