--- a/testing/marionette/client/marionette_driver/marionette.py
+++ b/testing/marionette/client/marionette_driver/marionette.py
@@ -1037,18 +1037,19 @@ class Marionette(object):
             self.delete_session()
             self.instance.restart(clean=clean)
 
         self.raise_for_port(self.wait_for_port())
         self.start_session(session_id=self.session_id)
         self._reset_timeouts()
 
         if in_app:
-            # In some cases Firefox restarts itself by spawning into a new process group. As long as
-            # mozrprocess cannot track that (bug 1176758) we assist by checking the new process id.
+            # In some cases Firefox restarts itself by spawning into a new process group.
+            # As long as mozprocess cannot track that behavior (bug 1284864) we assist by
+            # informing about the new process id.
             self.instance.runner.process_handler.check_for_detached(self.session['processId'])
 
     def absolute_url(self, relative_url):
         '''
         Returns an absolute url for files served from Marionette's www directory.
 
         :param relative_url: The url of a static file, relative to Marionette's www directory.
         '''