Check for empty guid

Jellyfin.Api/Controllers/TvShowsController.cs

@@ -278,7 +278,7 @@ namespace Jellyfin.Api.Controllers
             }
 
             // This must be the last filter
-            if (adjacentTo.HasValue)
+            if (adjacentTo.HasValue && !adjacentTo.Value.Equals(default))
             {
                 episodes = UserViewBuilder.FilterForAdjacency(episodes, adjacentTo.Value).ToList();
             }

MediaBrowser.Controller/Entities/Folder.cs

@@ -860,7 +860,7 @@ namespace MediaBrowser.Controller.Entities
                 return true;
             }
 
-            if (query.AdjacentTo.HasValue)
+            if (query.AdjacentTo.HasValue && !query.AdjacentTo.Value.Equals(default))
             {
                 Logger.LogDebug("Query requires post-filtering due to AdjacentTo");
                 return true;
@@ -1029,7 +1029,7 @@ namespace MediaBrowser.Controller.Entities
             #pragma warning restore CA1309
 
             // This must be the last filter
-            if (query.AdjacentTo.HasValue)
+            if (query.AdjacentTo.HasValue && !query.AdjacentTo.Value.Equals(default))
             {
                 items = UserViewBuilder.FilterForAdjacency(items.ToList(), query.AdjacentTo.Value);
             }

MediaBrowser.Controller/Entities/UserViewBuilder.cs

@@ -433,7 +433,7 @@ namespace MediaBrowser.Controller.Entities
             var user = query.User;
 
             // This must be the last filter
-            if (query.AdjacentTo.HasValue)
+            if (query.AdjacentTo.HasValue && !query.AdjacentTo.Value.Equals(default))
             {
                 items = FilterForAdjacency(items.ToList(), query.AdjacentTo.Value);
             }