diff --git a/src/applications/differential/query/DifferentialRevisionQuery.php b/src/applications/differential/query/DifferentialRevisionQuery.php
--- a/src/applications/differential/query/DifferentialRevisionQuery.php
+++ b/src/applications/differential/query/DifferentialRevisionQuery.php
@@ -466,9 +466,17 @@
       $basic_authors = $this->authors;
       $basic_reviewers = $this->reviewers;
 
+      $responsible_authors = array();
+      foreach ($this->responsibles as $responsible) {
+        $user_type = PhabricatorPeopleUserPHIDType::TYPECONST;
+        if (phid_get_type($responsible) === $user_type) {
+          $responsible_authors[] = $responsible;
+        }
+      }
+
       try {
         // Build the query where the responsible users are authors.
-        $this->authors = array_merge($basic_authors, $this->responsibles);
+        $this->authors = array_merge($basic_authors, $responsible_authors);
 
         $this->reviewers = $basic_reviewers;
         $selects[] = $this->buildSelectStatement($conn);