upsert returns 200 but does not persist entity

[jmcanterafonseca]

POST /ngsi-ld/v1/entityOperations/upsert

[{"id":"urn:ngsi-ld:ParkingSpot:santander:daoiz_velarde_1_5:3","type":"ParkingSpot","status":{"type":"Property","value":"free","observedAt":"2018-09-21T12:00:00Z"},"category":{"type":"Property","value":["onstreet"]},"refParkingSite":{"type":"Relationship","object":"urn:ngsi-ld:ParkingSite:santander:daoiz_velarde_1_5"},"name":{"type":"Property","value":"A-13"},"location":{"type":"GeoProperty","value":{"type":"Point","coordinates":[-3.80356167695194,43.46296641666926]}},"@context":["https://uri.etsi.org/ngsi-ld/v1/ngsi-ld-core-context.jsonld","https://schema.lab.fiware.org/ld/context"]}]

returns 200 but nothing is persisted