EF Core is attempting to update role instead of ContactRole for M-to-M table

Question

I am getting a "Primary key violation" error when EF Core is attempting to update a M-to-M relationship.

Here is the code:

// Find the Contact
Contact? Contact = await repository.GetEntityAsync(ContactDto?.Id ?? -1, cancellationToken);

// Check for null
if (Contact == null)
{
   return new OperationResultDto()
   {
      Success = false,
      Error = "Contact not found"
   };
}

mapper.Map(ContactDto, Contact);
Contact resultingContact = await repository.UpdateEntityAsync(Contact, cancellationToken); // << ERROR HERE

Here are the model classes:

public class ContactDto
{
    public int Id { get; set; }
    public IEnumerable<Role>? Roles { get; set; }
}

public class Contact 
{
    public int Id { get; set; }
    public virtual ICollection<Role>? Roles { get; set; }
}

public class Role 
{
    public Role() => Contacts = new HashSet<Contact>();
    
    public ContactType Type { get; set; }
    public virtual ICollection<Contact> Contacts { get; set; }
}

Fluent API:

/* Role Table */
modelBuilder.Entity<Role>(entity =>
{
    entity.HasKey(e => e.Type);

    entity.HasMany(e => e.Contacts)
          .WithMany(e => e.Roles);
});

/* Contact table */
modelBuilder.Entity<Contact>(entity =>
{
    entity.Property(e => e.TradingName).HasMaxLength(100);
    entity.Property(e => e.ParentId);

    entity.HasMany(e => e.Roles)
          .WithMany(e => e.Contacts);
});

When I look at the SQL in the debug it is this:

UPDATE [Contacts] 
SET [BreedEnumValue] = @p14, [CategoryEnumValue] = @p15, 
    [Destination] = @p16, [ERPStatus] = @p17, [EuComply] = @p18, 
    [Freight] = @p19, [Halal] = @p20, [MSA] = @p21, 
    [NonHGP] = @p22, [ParentId] = @p23, [QualityCode] = @p24, 
    [SaudiComply] = @p25, [Specie] = @p26, [TradingName] = @p27, 
    [TransportBy] = @p28, [TransportMode] = @p29
WHERE [Id] = @p30;

SELECT @@ROWCOUNT;

INSERT INTO [Role] ([Type])
VALUES (@p31), (@p32);

It is trying to update the Roles table, but the roles table is already populated. Why is this happening? Should it not find the TYPE ID?