@Entity(name = "AbstractEntity")
@Cacheable // NOTE: that all these entities are cacheable; if not -- issue is not reproducable.
public abstract class AbstractEntity {

	@Id
	@GeneratedValue
	private Integer id;
}

@Entity(name = "ConcreteEntity")
@Cacheable
public class ConcreteEntity extends AbstractEntity {

	private String content;
}

@Entity(name = "LazyAbstractEntityReference")
@Cacheable
public class LazyAbstractEntityReference {

	@Id
	@GeneratedValue
	private Integer id;

	@ManyToOne(fetch = FetchType.LAZY)
	private AbstractEntity entity; // NOTE: there's an `AbstractEntity` used. If a concrete entity type is used - issue is also not reproducable.
}