DataJpaTest using H2 not able to access data in Subselect Entity

I am running a unit test set up as a DataJpaTest with an H2 database. It worked well, until I introduced a new Immutable Entity set using a Subselect. It does not break, but it does not find data that it should. I see in the SQL that it is correctly joining to the Subselect query.

When running as normal as an application, the @Subselect entity works fine, so it is an issue with the unit test setup somehow.

Here is my Main entity:

@Entity
@DynamicUpdate
@Getter
@Setter
@EqualsAndHashCode(onlyExplicitlyIncluded = true, callSuper = false)
@Table(name = "apps", schema = "public")
public class App extends BaseEntity
{
    @Id
    @Column(name = "app_id", nullable = false)
    @GeneratedValue(strategy = GenerationType.SEQUENCE, generator = "ent_generator")
    @SequenceGenerator(name = "ent_generator", sequenceName = "entity_seq", allocationSize = 1)
    private long appId;

    @EqualsAndHashCode.Include
    @Basic
    @Column(name = "app_name", length = 200)
    private String appCode;

    @EqualsAndHashCode.Include
    @Basic
    @Column(name = "app_ver_name", length = 200)
    private String appVersion;

    @ManyToOne(fetch = FetchType.EAGER)
    @JoinColumn(name = "parent_app_id")
    private App parent;

    // ...

    @OneToMany(
            mappedBy = "app",
            cascade = CascadeType.ALL,
            orphanRemoval = true
    )
    private Set<TrainingRequirement> trainingRequirements = new HashSet<>();

    @OneToMany(mappedBy = "app")
    private Set<EffectiveTrainingRequirement> effectiveTrainingRequirements = new HashSet<>();

   // ...
}

Here is my @Subselect entity:

@Entity
@Immutable
@Subselect(
        "SELECT\n" +
        "     tr.trn_req_id AS trn_req_id\n" +
        "   , tr.app_id AS app_id\n" +
        "   FROM apps a\n" +
        "   JOIN training_reqs tr\n" +
        "-- ...")
@Synchronize({"apps","training_reqs"})
public class EffectiveTrainingRequirement
{
    @Id
    @Column(name = "trn_req_id", nullable = false)
    private long trainingRequirementId;

    @EqualsAndHashCode.Include
    @ManyToOne(fetch = FetchType.LAZY)
    @JoinColumn(name = "app_id")
    private App app;    
}

Here is the Unit test code (vastly reduced for relevant parts):

@RunWith(SpringRunner.class)
@DataJpaTest
public class TrainingRequirementRepositoryTest
{
    @Autowired
    private TestEntityManager entityManager;
    @Autowired
    private AppRepository appRepository;

    @Before
    public void setup()
    {
        // ...
        app4 = new App(organization, "a4");
        app4.addTrainingRequirement(new TrainingRequirement("treq6", c6));
        app4.addTrainingRequirement(new TrainingRequirement("treq7", c7, tr1));
        app4.addTrainingRequirement(new TrainingRequirement("treq8", c8, tr2));
        entityManager.persist(app4);

        app4v2 = new App(organization, "a4", app4, "v2");
        app4v2.setParent(app4);
        app4v2.addTrainingRequirement(treq7chg = new TrainingRequirement("treq7", c7, tr2));
        treq7chg.setChangeType(InheritOverride.CHANGE);
        app4v2.addTrainingRequirement(treq6rmv = new TrainingRequirement("treq6"));
        treq6rmv.setChangeType(InheritOverride.REMOVE);
        app4v2.addTrainingRequirement(treq9add = new TrainingRequirement("treq9", c9, tr4));
        treq9add.setChangeType(InheritOverride.ADDITION);
        entityManager.persist(app4v2);
    }

    @Test
    public void test_AppWithEffectiveTR()
    {
        App app = appRepository.getAppWithParent(organization, "a4", "v2").get();

        logger.debug("# tr: "+app.getTrainingRequirements().size());
        logger.debug("# etr: "+app.getEffectiveTrainingRequirements().size());
        for (EffectiveTrainingRequirement tr : app.getEffectiveTrainingRequirements())
            logger.debug("tr: "+tr.toString());
    }

}

The repository:

@Repository
public interface AppRepository extends CrudRepository<App, Long>
{
    String APP_FETCH_QUERY = "SELECT a FROM App a " +
                             "LEFT JOIN FETCH a.parent p " +
                             "LEFT JOIN FETCH a.trainingRequirements atr " +
                             "LEFT JOIN FETCH a.effectiveTrainingRequirements ";

    @Query(value = APP_FETCH_QUERY +
                   "WHERE a.organization = :org " +
                   " AND a.appCode = :appCode " +
                   " AND a.appVersion = :appVersion" )
    Optional<App> getAppWithParent(@Param("org") Organization org,
                                   @Param("appCode") String appCode,
                                   @Param("appVersion") String appVersion);
}