How to test fluent-NHibernate's PersistenceSpecification.VerifyTheMappings with lists and relational objects?

public class RecipientListMap : ClassMap<RecipientList>
{

    public RecipientListMap()
    {
        Id(x => x.ID);
        Map(x => x.ApplicationID);
        Map(x => x.Name);
        Map(x => x.IsDeleted);
        HasMany<Recipient>(x => x.Recipients).WithKeyColumn("RecipientListID").AsList().LazyLoad();
    }

}

private IList<Recipient> _recipients = new List<Recipient>()
        {
            new Recipient { FirstName = "Joe", LastName = "Bloggs", Email = "[email protected]", IsDeleted = false },
            new Recipient { FirstName = "John", LastName = "Doe", Email = "[email protected]", IsDeleted = false },
            new Recipient { FirstName = "Jane", LastName = "Smith", Email = "[email protected]", IsDeleted = false }
        };

        [Test]
        public void Can_Add_RecipientList_To_Database()
        {
            new PersistenceSpecification<RecipientList>(Session)
                .CheckProperty(x => x.Name, "My List")
                .CheckProperty(x => x.Columns, "My columns")
                .CheckProperty(x => x.IsDeleted, false)
                .CheckProperty(x => x.ApplicationID, Guid.NewGuid())
                .CheckProperty(x => x.Recipients, _recipients)
                .VerifyTheMappings();
        }

failed: System.ApplicationException : Expected 'System.Collections.Generic.List`1[Project.Data.Domains.Recipients.Recipient]' but got 'NHibernate.Collection.Generic.PersistentGenericBag`1[Project.Data.Domains.Recipients.Recipient]' for Property 'Recipients'