diff --git a/app/templates/ExternalIdentitySources/search.php b/app/templates/ExternalIdentitySources/search.php
index 094ae6b0a..4c3674b2e 100644
--- a/app/templates/ExternalIdentitySources/search.php
+++ b/app/templates/ExternalIdentitySources/search.php
@@ -133,7 +133,8 @@
           <tr class="linked-row">
             <td>
               <?= $this->Html->link(
-                    $source_key,
+                    // Cast to string in case we have a numeric source key
+                    (string)$source_key,
                     [
                       'action' => 'retrieve',
                       $this->request->getParam('pass')[0],