Spring @GenericGenerator ignoring Object relationships

Question

I'm having some issues using Springs @GenericGenerator with an object with a @ManyToMany relationship. The generator is wired up correctly, and is being used to generate an ID for my entity. However, the @ManyToMany entity that i'm using the generate the ID seems to be missing when the generate method is called.

I have my first Entity, with the generator and the relationship

public class Donor {

    @Id
    @GenericGenerator(name = "donor_id", strategy = "path.to.my.CustomDonorIdGenerator")
    @GeneratedValue(generator = "donor_id")
    private String id;

    @ManyToMany(cascade = CascadeType.ALL, fetch = FetchType.EAGER)
    private Set<Address> addresses = new HashSet<>();

    ...more fields and good stuff

When I stop the code on a breakpoint before my repository.save() the Donor object has the relationship:

However, my next break point within the generator is missing the addresses:

    @Override
    public Serializable generate(SharedSessionContractImplementor session, Object o) throws HibernateException {
        Connection connection = session.connection();

        try {
            Donor donor = (Donor) o;

         ... generate the stuff.

I did notice that the Object number is different - so I'm assuming it's creating a copy of the object, but not correctly carrying over the relationship. Is there some way to carry this over correctly?