I don't speak Spanish but I think I know what you mean. Your opponent probably had set a conditional move. If you make the move he expected you to make then his move will be made automatically, whether he is online or not.
Look here: http://support.chess.com/index.php?_m=knowledgebase&_a=viewarticle&kbarticleid=673
Alguien del T. México me podría explicar como puede un jugador responder instantáneamente una jugada sin aun estar en línea.