I am trying to set a custom value on the member item when the member is created for the first time.

But when I call the save method on the member the custom property value does not appear in Umbraco CMS but debugging the code I can see the custom properties have their value set in after the setValue method. Any ideas why this is not presenting or saving in Umbraco 8 CMS? There are no errors thrown.

    private void MemberService_Saving(IMemberService sender, SaveEventArgs<IMember> e)
    {

                foreach (IMember member in e.SavedEntities)
                {
                    if (member.Id <= 0)
                    {
                        var guidId = Guid.NewGuid().ToString();
                        member.SetValue("customFieldName", guidId);
                        sender.Save(member, false);
                    }
                }
   }