Stale Index Issue

Audio_Index.cs

public Audio_Index()
        {
            // audio properties
            Map = audios => from audio in audios
                                        select new
                                                   {
                                                       Id = audio.Id,
                                                       AudioId = audio.Id,
                                                       AccountId = audio.AccountId,
                                                       ArtistName = audio.ArtistName,
                                                       AudioType = audio.AudioType,
                                                       Identifier = audio.Identifier,
                                                       Name = audio.Name,
                                                       Status = audio.Status,
                                                       Visible = audio.Visible,
                                                       Tags = audio.Tags,
                                                       Genre_Code = audio.Genre.Code,
                                                       DateAdded = audio.DateAdded,

                                                       WeeksDownloads = audio.WeeksDownloads,
                                                       WeeksPlays = audio.WeeksPlays,
                                                       WeeksFavourites = audio.WeeksFavourites,
                                                       WeeksLikes = audio.WeeksLikes,
                                                       WeeksComments = audio.WeeksComments,

                                                       TotalDownloads = audio.TotalDownloads,
                                                       TotalPlays = audio.TotalPlays,
                                                       TotalFavourites = audio.TotalFavourites,
                                                       TotalLikes = audio.TotalLikes,
                                                       TotalComments = audio.TotalComments,

                                                       NhibernateAudioId = audio.NhibernateAudioId
                                                   };
           
            //Sort(x => x.TotalPlays, SortOptions.Int);
            //Sort(x => x.TotalDownloads, SortOptions.Int);
            //Sort(x => x.TotalComments, SortOptions.Int);
            //Sort(x => x.TotalFavourites, SortOptions.Int);
            //Sort(x => x.TotalLikes, SortOptions.Int);
            //Sort(x => x.WeeksPlays, SortOptions.Int);
            //Sort(x => x.WeeksDownloads, SortOptions.Int);
            //Sort(x => x.WeeksComments, SortOptions.Int);
            //Sort(x => x.WeeksFavourites, SortOptions.Int);
            //Sort(x => x.WeeksLikes, SortOptions.Int);

            //Analyzers.Add(x => x.Name, "SimpleAnalyzer");
        }

Tag_Count.cs

 public class Tag_Count : AbstractIndexCreationTask<Audio, Tag_Count.ReduceResult>
    {
        public class ReduceResult
        {
            public string Name { get; set; }
            public int Count { get; set; }
        }

        public Tag_Count()
        {
            Map = audios => from audio in audios
                           from tag in audio.Tags
                           select new { Name = tag.ToString().ToLower(), Count = 1 };

            Reduce = results => from tagCount in results
                                group tagCount by tagCount.Name
                                    into g
                                    select new { Name = g.Key, Count = g.Sum(x => x.Count) };

            //Sort(x => x.Count, SortOptions.Int);

            //Analyzers.Add(x => x.Name, "SimpleAnalyzer");
        }
    }