Hibernate multiple natural id within an entity

I have a jpa entity "user" which has 2 business keys username and email. These 2 fields are unique and i have tried to define both fields as naturalId with @NaturalId, however when i search the user entity by passing only username or email, hibernate throw an exception complaining about the missing value of a another naturalid because hibernate treated both fields as a composite natural id. Is this the limitation of hibernate or there is an alternative to solve this error?

@Entity
@Table(name = "user",
       indexes = { @Index(columnList = "login"),
                   @Index(columnList = "email")},
       uniqueConstraints = { @UniqueConstraint(columnNames = { "login" }),
                             @UniqueConstraint(columnNames = { "email" })})
@Cache(usage = CacheConcurrencyStrategy.READ_WRITE)
@org.hibernate.annotations.NaturalIdCache
public class User {

    @org.hibernate.annotations.NaturalId(mutable = true)
    private String login;

    @org.hibernate.annotations.NaturalId(mutable = true)
    private String email;

    ...
}

When I call the code below:

User entity = em.unwrap(Session.class)          
    .byNaturalId(User.class)
    .using("login", "abc123")
    .load();

or

User entity = em.unwrap(Session.class)          
    .byNaturalId(User.class)
    .using("email", "abc123@xyz.com")
    .load();

I encountered error complaining about missing of another natural id. I have to set both natural id which was not what i want

User entity = em.unwrap(Session.class)          
    .byNaturalId(User.class)
    .using("login", "abc123")
    .using("email", "abc123@xyz.com")
    .load();