diff --git a/lib/tests/behat/behat_hooks.php b/lib/tests/behat/behat_hooks.php
index bbbe7ccc67f..43582fcdb42 100644
--- a/lib/tests/behat/behat_hooks.php
+++ b/lib/tests/behat/behat_hooks.php
@@ -250,7 +250,7 @@ class behat_hooks extends behat_base {
             // PHP debug messages.
             $phperrorxpath = "//div[@data-rel='phpdebugmessage']";
             // Any other backtrace.
-            $othersxpath = "//*[contains(., ': call to ')])[1]";
+            $othersxpath = "(//*[contains(., ': call to ')])[1]";
 
             $xpaths = array($exceptionsxpath, $debuggingxpath, $phperrorxpath, $othersxpath);
             $joinedxpath = implode(' | ', $xpaths);