diff --git a/backend/src/Service/Ingestion/IngestionService.php b/backend/src/Service/Ingestion/IngestionService.php
index e8ba90f..47ac937 100644
--- a/backend/src/Service/Ingestion/IngestionService.php
+++ b/backend/src/Service/Ingestion/IngestionService.php
@@ -222,19 +222,23 @@ class IngestionService
 
     private function updateSpatialMeta(string $id): void
     {
-        // 1) Filtrer les micro-polygones < MIN_POLYGON_AREA_M2 avant simplification
-        //    Un fragment < 1 km² en plein océan est du bruit ou un artefact atmo.
+        // 1) Filtrer les micro-polygones < MIN_POLYGON_AREA_M2 avant simplification.
+        //    ST_CollectionExtract(..., 3) extrait uniquement les Polygon pour éviter
+        //    que ST_Collect retourne une GeometryCollection incompatible avec la colonne.
+        //    ST_Multi force le type MultiPolygon même pour un seul polygone résiduel.
         $this->em->getConnection()->executeStatement(
             "UPDATE sargassum_observation
              SET geometry = (
                 SELECT COALESCE(
-                    ST_Collect(geom),
-                    'GEOMETRYCOLLECTION EMPTY'::geometry
+                    ST_Multi(ST_CollectionExtract(ST_Collect(geom), 3)),
+                    ST_GeomFromText('MULTIPOLYGON EMPTY', 4326)
                 )
                 FROM (
                     SELECT (ST_Dump(geometry)).geom AS geom
+                    FROM sargassum_observation
+                    WHERE id = :id
                 ) parts
-                WHERE ST_Area(geom::geography) >= :minArea
+                WHERE ST_Area(parts.geom::geography) >= :minArea
              )
              WHERE id = :id",
             ['id' => $id, 'minArea' => self::MIN_POLYGON_AREA_M2]