diff --git a/core/dbobject.class.php b/core/dbobject.class.php
index 19a64c5ba..ea70321cf 100644
--- a/core/dbobject.class.php
+++ b/core/dbobject.class.php
@@ -4229,7 +4229,7 @@ abstract class DBObject implements iDisplay
 			}
 		}
 		$oDate->modify($sModifier);
-		$this->Set($sAttCode, $oDate->format('Y-m-d H:i:s'));
+		$this->Set($sAttCode, $oDate->getTimestamp());
 	}
 
 	/**
diff --git a/tests/php-unit-tests/unitary-tests/core/DBObjectTest.php b/tests/php-unit-tests/unitary-tests/core/DBObjectTest.php
index 6cf5b2604..5f1fe127e 100644
--- a/tests/php-unit-tests/unitary-tests/core/DBObjectTest.php
+++ b/tests/php-unit-tests/unitary-tests/core/DBObjectTest.php
@@ -539,4 +539,31 @@ class DBObjectTest extends ItopDataTestCase
 
 		return $oUserWithAllowedOrgs;
 	}
+
+
+	/**
+	 * @covers DBObject::SetComputedDate
+	 * @return void
+	 */
+	public function testSetComputedDateOnAttributeDate()
+	{
+		$oObject = MetaModel::NewObject(\CustomerContract::class, ['name' => 'Test contract', 'org_id' => '3', 'provider_id' => '2']);
+		$oObject->Set('start_date', time());
+		$oObject->SetComputedDate('end_date', "+2 weeks", 'start_date');
+		$this->assertTrue(true, 'No fatal error on computing date');
+	}
+
+	/**
+	 * @covers DBObject::SetComputedDate
+	 * @return void
+	 */
+	public function testSetComputedDateOnAttributeDateTime()
+	{
+		$oObject = MetaModel::NewObject(\WorkOrder::class, ['name' => 'Test workorder', 'description' => 'Toto']);
+		$oObject->Set('start_date', '2024-01-01 09:45:00');
+		$oObject->SetComputedDate('end_date', "+2 weeks", 'start_date');
+		$this->assertTrue(true, 'No fatal error on computing date');
+		$this->assertEquals("2024-01-15 09:45:00", $oObject->Get('end_date'), 'SetComputedDate +2 weeks on a WorkOrder DateTimeAttribute');
+
+	}
 }