diff --git a/src/applications/repository/worker/PhabricatorRepositoryCommitOwnersWorker.php b/src/applications/repository/worker/PhabricatorRepositoryCommitOwnersWorker.php
--- a/src/applications/repository/worker/PhabricatorRepositoryCommitOwnersWorker.php
+++ b/src/applications/repository/worker/PhabricatorRepositoryCommitOwnersWorker.php
@@ -106,9 +106,10 @@
     $commit_reviewedby_phid = null;
 
     if ($revision_id) {
-      // TODO: (T603) This is probably safe to use an omnipotent user on,
-      // but check things more closely.
-      $revision = id(new DifferentialRevision())->load($revision_id);
+      $revision = id(new DifferentialRevisionQuery())
+        ->setViewer(PhabricatorUser::getOmnipotentUser())
+        ->withIDs(array($revision_id))
+        ->executeOne();
       if ($revision) {
         $revision_author_phid = $revision->getAuthorPHID();
         $commit_reviewedby_phid = $data->getCommitDetail('reviewerPHID');