Allegation, by way of objection to enforcement without security, of nullity of the arbitration award on the grounds of nullity of the arbitration clause. Parties that reached a settlement within the arbitration proceedings and had it ratified. Venire contra factum proprium. The allegation of nullity should have been raised at the first opportunity after the institution of the arbitration, in the challenge to the enforcement of the judgment ratifying the settlement, or in a separate lawsuit, under penalty of preclusion, which did not occur: