FIX: Only use cached list when we have less than 1 page worth of topics.

We only need it then to maintain the scroll position.

app/assets/javascripts/discourse/models/topic_list.js

@@ -206,9 +206,10 @@ Discourse.TopicList.reopenClass({
       if (extras.cached) {
         var cachedList = session.get('topicList');
 
-        // Try to use the cached version
+        // Try to use the cached version if it exists and is greater than the topics per page
         if (cachedList && (cachedList.get('filter') === filter) &&
-                 _.isEqual(cachedList.get('listParams'), filterParams)) {
+            (cachedList.get('topics.length') || 0) > Discourse.SiteSettings.topics_per_page &&
+            _.isEqual(cachedList.get('listParams'), filterParams)) {
           cachedList.set('loaded', true);
 
           if (tracking) {

config/site_settings.yml

@@ -154,6 +154,7 @@ basic:
   topics_per_page:
     default: 30
     min: 1
+    client: true
   show_subcategory_list:
     default: false
     client: true