Spatial indexes and Unable to execute a query with a subquery using a join on spatial data with another table.

When I query my database using spatial functions, queries are sanctioned by an error message Unable to execute a query with a subquery using a join on spatial data with another table. Having read the various posts on the subject, I have come to delete one of the spatial indexes even though it is a Point type column. Without this index, queries work slowly but they don't crash.

Below is a query used; after dropping the index on wnat_gps.p_coordonnees_spacial, the query works.

SELECT SITE.set_name, SITE.site_name, wnat_gps.unik_lieudit AS unik_lieudit, wnat_gps.unik AS unik_gps, 'G' AS Type_Localite, point(0,0) AS lieudit_p_coordonnees_spacial, wnat_gps.p_coordonnees_spacial AS gps_p_coordonnees_spacial, ST_ASTEXT(ST_CENTROID(SITE.g_coordinates_spacial)) AS Centroid FROM ( SELECT wnat_geometries_objets.unik AS unik_geometrie_objet, wnat_geometries_ensembles.unik_organism, wnat_geometries_ensembles.unik_territoire, organisms.Organism, wnat_geometries_sets.set_name, wnat_geometries_sites.site_name, wnat_geometries_objets.g_coordonnees_spacial, wnat_geometries_sites.unik_geometrie_ensemble, wnat_geometries_objets.unik_geometrie_site FROM wnat_geometries_sites INNER JOIN wnat_geometries_ensembles ON wnat_geometries_sites.unik_geometrie_ensemble = wnat_geometries_ensembles.unik INNER JOIN wnat_geometries_objets ON wnat_geometries_objets.unik_geometrie_site = wnat_geometries_sites.unik INNER JOIN organisms ON wnat_geometries_ensembles.unik_organism = organisms.unik WHERE wnat_geometries_ensembles.ensemble_name = 'CDL Corse (PI)' ) SITE, wnat_gps WHERE ST_CONTAINS(SITE.g_coordonnees_spacial, wnat_gps.p_coordonnees_spacial)