N°6299 - DBUpdate regression in 3.1 when setting a field with same value in the concerned object

core/cmdbobject.class.inc.php

@@ -519,6 +519,15 @@ abstract class CMDBObject extends DBObject
 			utils::PopArchiveMode();
 		}
 	}
+
+	public function DBUpdate()
+	{
+		if (count($this->ListChanges()) === 0) {
+			$this->InitPreviousValuesForUpdatedAttributes();
+			return $this->GetKey();
+		}
+		return parent::DBUpdate(); // TODO: Change the autogenerated stub
+	}
 }