diff --git a/app/Jobs/ServerManagerJob.php b/app/Jobs/ServerManagerJob.php
index a618647eb..61266473b 100644
--- a/app/Jobs/ServerManagerJob.php
+++ b/app/Jobs/ServerManagerJob.php
@@ -120,7 +120,7 @@ private function processServerTasks(Server $server): void
         // Check if we should run sentinel-based checks
         $lastSentinelUpdate = $server->sentinel_updated_at;
         $waitTime = $server->waitBeforeDoingSshCheck();
-        $sentinelOutOfSync = Carbon::parse($lastSentinelUpdate)->isBefore($this->executionTime->subSeconds($waitTime));
+        $sentinelOutOfSync = Carbon::parse($lastSentinelUpdate)->isBefore($this->executionTime->copy()->subSeconds($waitTime));
 
         if ($sentinelOutOfSync) {
             // Dispatch ServerCheckJob if Sentinel is out of sync
diff --git a/tests/Unit/ServerManagerJobExecutionTimeTest.php b/tests/Unit/ServerManagerJobExecutionTimeTest.php
new file mode 100644
index 000000000..d32db6834
--- /dev/null
+++ b/tests/Unit/ServerManagerJobExecutionTimeTest.php
@@ -0,0 +1,97 @@
+<?php
+
+use Illuminate\Support\Carbon;
+
+afterEach(function () {
+    Carbon::setTestNow();
+});
+
+it('does not mutate Carbon instance when using copy() before subSeconds()', function () {
+    // This test verifies the fix for the bug where subSeconds() was mutating executionTime
+    $originalTime = Carbon::parse('2024-12-02 12:00:00');
+    $originalTimeString = $originalTime->toDateTimeString();
+
+    // Simulate what happens in processServerTasks() with the FIX applied
+    $waitTime = 360;
+    $threshold = $originalTime->copy()->subSeconds($waitTime);
+
+    // The original time should remain unchanged after using copy()
+    expect($originalTime->toDateTimeString())->toBe($originalTimeString);
+    expect($threshold->toDateTimeString())->toBe('2024-12-02 11:54:00');
+});
+
+it('demonstrates mutation bug when not using copy()', function () {
+    // This test shows what would happen WITHOUT the fix (the bug)
+    $originalTime = Carbon::parse('2024-12-02 12:00:00');
+
+    // Simulate what would happen WITHOUT copy() (the bug)
+    $waitTime = 360;
+    $threshold = $originalTime->subSeconds($waitTime);
+
+    // Without copy(), the original time is mutated!
+    expect($originalTime->toDateTimeString())->toBe('2024-12-02 11:54:00');
+    expect($threshold->toDateTimeString())->toBe('2024-12-02 11:54:00');
+    expect($originalTime)->toBe($threshold); // They're the same object
+});
+
+it('preserves executionTime across multiple subSeconds calls with copy()', function () {
+    // Simulate processing multiple servers with different wait times
+    $executionTime = Carbon::parse('2024-12-02 12:00:00');
+    $originalTimeString = $executionTime->toDateTimeString();
+
+    // Server 1: waitTime = 360s
+    $threshold1 = $executionTime->copy()->subSeconds(360);
+    expect($executionTime->toDateTimeString())->toBe($originalTimeString);
+    expect($threshold1->toDateTimeString())->toBe('2024-12-02 11:54:00');
+
+    // Server 2: waitTime = 300s (should still use original time)
+    $threshold2 = $executionTime->copy()->subSeconds(300);
+    expect($executionTime->toDateTimeString())->toBe($originalTimeString);
+    expect($threshold2->toDateTimeString())->toBe('2024-12-02 11:55:00');
+
+    // Server 3: waitTime = 360s (should still use original time)
+    $threshold3 = $executionTime->copy()->subSeconds(360);
+    expect($executionTime->toDateTimeString())->toBe($originalTimeString);
+    expect($threshold3->toDateTimeString())->toBe('2024-12-02 11:54:00');
+
+    // Server 4: waitTime = 300s (should still use original time)
+    $threshold4 = $executionTime->copy()->subSeconds(300);
+    expect($executionTime->toDateTimeString())->toBe($originalTimeString);
+    expect($threshold4->toDateTimeString())->toBe('2024-12-02 11:55:00');
+
+    // Server 5: waitTime = 360s (should still use original time)
+    $threshold5 = $executionTime->copy()->subSeconds(360);
+    expect($executionTime->toDateTimeString())->toBe($originalTimeString);
+    expect($threshold5->toDateTimeString())->toBe('2024-12-02 11:54:00');
+
+    // The executionTime should STILL be exactly the original time
+    expect($executionTime->toDateTimeString())->toBe('2024-12-02 12:00:00');
+});
+
+it('demonstrates compounding bug without copy() across multiple calls', function () {
+    // This shows the compounding bug that happens WITHOUT the fix
+    $executionTime = Carbon::parse('2024-12-02 12:00:00');
+
+    // Server 1: waitTime = 360s
+    $threshold1 = $executionTime->subSeconds(360);
+    expect($executionTime->toDateTimeString())->toBe('2024-12-02 11:54:00'); // MUTATED!
+
+    // Server 2: waitTime = 300s (uses already-mutated time)
+    $threshold2 = $executionTime->subSeconds(300);
+    expect($executionTime->toDateTimeString())->toBe('2024-12-02 11:49:00'); // Further mutated!
+
+    // Server 3: waitTime = 360s (uses even more mutated time)
+    $threshold3 = $executionTime->subSeconds(360);
+    expect($executionTime->toDateTimeString())->toBe('2024-12-02 11:43:00'); // Even more mutated!
+
+    // Server 4: waitTime = 300s
+    $threshold4 = $executionTime->subSeconds(300);
+    expect($executionTime->toDateTimeString())->toBe('2024-12-02 11:38:00');
+
+    // Server 5: waitTime = 360s
+    $threshold5 = $executionTime->subSeconds(360);
+    expect($executionTime->toDateTimeString())->toBe('2024-12-02 11:32:00');
+
+    // The executionTime is now 1680 seconds (28 minutes) earlier than it should be!
+    expect($executionTime->diffInSeconds(Carbon::parse('2024-12-02 12:00:00')))->toEqual(1680);
+});