Workaround to ensure the view uses a unique cloned collection for filtering instead of affecting the generic SeriesCollection.

src/UI/Series/Index/SeriesIndexLayout.js

@@ -127,10 +127,16 @@ define(
                     ]
             },
 
-            sortingOptions: {
+            initialize: function () {
+                this.seriesCollection = SeriesCollection.clone();
+
+                this.listenTo(SeriesCollection, 'sync', this._renderView);
+                this.listenTo(SeriesCollection, 'remove', this._renderView);
+
+                this.sortingOptions = {
                     type          : 'sorting',
                     storeState    : false,
-                viewCollection: SeriesCollection,
+                    viewCollection: this.seriesCollection,
                     items         :
                         [
                             {
@@ -159,13 +165,7 @@ define(
                                 name : 'percentOfEpisodes'
                             }
                         ]
-            },
-
-            initialize: function () {
-                this.seriesCollection = SeriesCollection;
-
-                this.listenTo(SeriesCollection, 'sync', this._renderView);
-                this.listenTo(SeriesCollection, 'remove', this._renderView);
+                };
 
                 this.filteringOptions = {
                     type         : 'radio',