The following are illegal:
1° Deliberations in which one or more members of the territorial council with an interest in the matter that is the subject of the deliberation have taken part, either in their personal name or as agents;
2° Decisions and deliberations by which the local authority waives, either directly or by means of a contractual clause, the right to bring any liability action against any natural or legal person that it remunerates in any form whatsoever.