diff --git a/app/assets/javascripts/discourse/models/post_stream.js b/app/assets/javascripts/discourse/models/post_stream.js
index 9888d5d8f..0a38c5c8d 100644
--- a/app/assets/javascripts/discourse/models/post_stream.js
+++ b/app/assets/javascripts/discourse/models/post_stream.js
@@ -470,7 +470,10 @@ Discourse.PostStream = Em.Object.extend({
     @returns {Discourse.Post} the post that was inserted.
   **/
   appendPost: function(post) {
-    this.get('posts').addObject(this.storePost(post));
+    var stored = this.storePost(post);
+    if (stored) {
+      this.get('posts').addObject(stored);
+    }
     return post;
   },
 
@@ -683,7 +686,7 @@ Discourse.PostStream = Em.Object.extend({
     @returns {Discourse.Post} the post from the identity map
   **/
   storePost: function(post) {
-    var postId = post.get('id');
+    var postId = Em.get(post, 'id');
     if (postId) {
       var postIdentityMap = this.get('postIdentityMap'),
           existing = postIdentityMap.get(post.get('id'));