diff --git a/CHANGELOG b/CHANGELOG
index 12f612830..419fd32e4 100644
--- a/CHANGELOG
+++ b/CHANGELOG
@@ -1,6 +1,8 @@
 CHANGELOG Roundcube Webmail
 ===========================
 
+- Fix bug where contacts search could skip some records (#6130)
+
 RELEASE 1.3.4
 -------------
 - Fix a couple of warnings on PHP 7.2 (#6098)
diff --git a/program/lib/Roundcube/rcube_addressbook.php b/program/lib/Roundcube/rcube_addressbook.php
index e670214d5..e7d431b74 100644
--- a/program/lib/Roundcube/rcube_addressbook.php
+++ b/program/lib/Roundcube/rcube_addressbook.php
@@ -654,13 +654,16 @@ abstract class rcube_addressbook
      */
     public static function compose_contact_key($contact, $sort_col)
     {
-        $key = $contact[$sort_col] . ':' . $contact['sourceid'];
+        $key = $contact[$sort_col];
 
         // add email to a key to not skip contacts with the same name (#1488375)
         if (($email = self::get_col_values('email', $contact, true)) && !empty($email)) {
             $key .= ':' . implode(':', (array)$email);
         }
 
+        // Make the key really unique (as we e.g. support contacts with no email)
+        $key .= ':' . $contact['sourceid'] . ':' . $contact['ID'];
+
         return $key;
     }