Deal Update method AssociateContacts was not updated

[shidcordero]

        DealHubSpot deal = null;

        if (position.HubSpotDealId.HasValue)
        {
            deal = hubSpotApi.Deal.GetById<DealHubSpot>(position.HubSpotDealId.Value);
        } 
        else
        {
            deal = new DealHubSpot();
            deal.Associations.AssociatedCompany = new long[] { position.Employer.HubSpotCompanyId.Value };
        }

        deal.Name = $"{position.Employer.Name} - {position.PositionType.Name} - {position.ExperienceLevel.Name}";
        deal.DealType = position.PositionType.Name;
        deal.ExperienceLevel = position.ExperienceLevel.Name;
        deal.Location = position.Location.Name;
        deal.DealStatus = position.PositionStatus.Name;
        deal.Associations.AssociatedContacts = position.PositionCandidates
            .Where(x => x.Candidate.User.HubSpotContactId.HasValue)
            .Select(x => x.Candidate.User.HubSpotContactId.Value)
            .ToArray();
        

        if (position.HubSpotDealId.HasValue)
        {
            hubSpotApi.Deal.Update(deal);
        }
        else
        {
            deal = hubSpotApi.Deal.Create(deal);
        }

The code above works when the Create method is called, but when using Update to update the AssociatedContacts, it won't work. There's no error thrown so I don't know what workaround to implement.