The information displayed on idealista/maps comes from various public sources, the land registry or cadastre and non-personal data from listings published on idealista. The information from the land registry is unprotected public information that anyone can access on the Spanish land registry online portal. idealista/maps indexes this information and publishes exactly what appears in the cadastre.
idealista does not intervene or manipulate any of this cadastral data. For any claim related to cadastral information you should contact the land registry in Spain.