Fix for endorsement 403 error

common/static/coffee/src/discussion/utils.coffee

@@ -181,11 +181,13 @@ class @DiscussionUtil
           params["$loading"].loaded()
     return request
 
-  @updateWithUndo: (model, updates, safeAjaxParams, errorMsg) ->
+  @updateWithUndo: (model, updates, safeAjaxParams, errorMsg, beforeSend) ->
     if errorMsg
       safeAjaxParams.error = => @discussionAlert(gettext("Sorry"), errorMsg)
     undo = _.pick(model.attributes, _.keys(updates))
     model.set(updates)
+    if beforeSend?
+      beforeSend()
     @safeAjax(safeAjaxParams).fail(() -> model.set(undo))
 
   @bindLocalEvents: ($local, eventsHandler) ->

common/static/coffee/src/discussion/views/discussion_content_view.coffee

@@ -211,8 +211,9 @@ if Backbone?
       DiscussionUtil.updateWithUndo(
         @model,
         updates,
-        {url: url, type: "POST", data: {endorsed: is_endorsing}, beforeSend: beforeFunc, $elem: $(event.currentTarget)},
-        msg
+        {url: url, type: "POST", data: {endorsed: is_endorsing}, $elem: $(event.currentTarget)},
+        msg,
+        beforeFunc
       ).always(@trigger("comment:endorse")) # ensures UI components get updated to the correct state when ajax completes
 
     toggleVote: (event) =>