diff --git a/app/Jobs/ProcessTrackingPayload.php b/app/Jobs/ProcessTrackingPayload.php
index c02fb80..f0a8817 100644
--- a/app/Jobs/ProcessTrackingPayload.php
+++ b/app/Jobs/ProcessTrackingPayload.php
@@ -110,9 +110,14 @@ class ProcessTrackingPayload implements ShouldQueue
             ]);
         }
 
+        // Calculate duration, ensuring it's never negative (handle out-of-order events)
+        // Use max() to ensure we use the latest timestamp for ended_at
+        $endedAt = $session->ended_at ? max($now, $session->ended_at) : $now;
+        $duration = max(0, (int) $endedAt->diffInSeconds($session->started_at, false));
+
         $session->update([
-            'ended_at' => $now,
-            'duration' => $now->diffInSeconds($session->started_at),
+            'ended_at' => $endedAt,
+            'duration' => $duration,
             'exit_page' => $this->payload['path'] ?? $this->payload['url'] ?? $session->exit_page,
             'pages_count' => $session->pageViews()->count(),
             'is_bounce' => $session->pageViews()->count() <= 1,