diff --git a/Slack.php b/Slack.php
index ae5c40a..33372e6 100644
--- a/Slack.php
+++ b/Slack.php
@@ -302,9 +302,11 @@ public function sendReport(
         // Safeguard against sending the same report twice to the same Slack channel (unless $force is true)
         if (!$force && $this->reportAlreadySent($report, $period)) {
             $logger->warning(
-                'Preventing the same scheduled report from being sent again (report #%s for period "%s")',
-                $report['idreport'],
-                $prettyDate
+                sprintf(
+                    'Preventing the same scheduled report from being sent again (report #%s for period "%s")',
+                    $report['idreport'],
+                    $prettyDate
+                )
             );
             return;
         }
diff --git a/tests/UI/expected-ui-screenshots/CustomAlerts_send_via_slack_new.png b/tests/UI/expected-ui-screenshots/CustomAlerts_send_via_slack_new.png
index a00b84e..d39caac 100644
Binary files a/tests/UI/expected-ui-screenshots/CustomAlerts_send_via_slack_new.png and b/tests/UI/expected-ui-screenshots/CustomAlerts_send_via_slack_new.png differ