diff --git a/app/components/debug-panel/DebugPanel.tsx b/app/components/debug-panel/DebugPanel.tsx
index 31a4b7f05..f6752826a 100644
--- a/app/components/debug-panel/DebugPanel.tsx
+++ b/app/components/debug-panel/DebugPanel.tsx
@@ -125,8 +125,7 @@ const DebugConfigurator = () => {
             size="small"
             href={`${sparqlEditorUrl}#query=${encodeURIComponent(
               `#pragma describe.strategy cbd
-               #pragma join.hash off
-              
+
                DESCRIBE <${cube.iri}>`
             )}&requestMethod=POST`}
             target="_blank"
diff --git a/app/graphql/context.tsx b/app/graphql/context.tsx
index bd3623612..6efb5b990 100644
--- a/app/graphql/context.tsx
+++ b/app/graphql/context.tsx
@@ -10,9 +10,9 @@ import { LRUCache } from "typescript-lru-cache";
 import { SPARQL_GEO_ENDPOINT } from "@/domain/env";
 import { Awaited } from "@/domain/types";
 import { Timings } from "@/gql-flamegraph/resolvers";
-import { createSource } from "@/rdf/create-source";
+import { createSource, pragmas } from "@/rdf/create-source";
 import { ExtendedCube } from "@/rdf/extended-cube";
-import { timed, TimingCallback } from "@/utils/timed";
+import { TimingCallback, timed } from "@/utils/timed";
 
 import { createCubeDimensionValuesLoader } from "../rdf/queries";
 import {
@@ -27,7 +27,7 @@ import { RequestQueryMeta } from "./query-meta";
 export const MAX_BATCH_SIZE = 500;
 
 export const getRawCube = async (sparqlClient: ParsingClient, iri: string) => {
-  const source = createSource(sparqlClient);
+  const source = createSource(sparqlClient, pragmas);
   const cube = new ExtendedCube({
     parent: source,
     term: rdf.namedNode(iri),
diff --git a/app/rdf/create-source.ts b/app/rdf/create-source.ts
index 1ce24882b..46d762cf1 100644
--- a/app/rdf/create-source.ts
+++ b/app/rdf/create-source.ts
@@ -6,11 +6,14 @@ export const pragmas = `#pragma describe.strategy cbd
 #pragma join.hash off
 `;
 
-export const createSource = (sparqlClient: ParsingClient) => {
+export const createSource = (
+  sparqlClient: ParsingClient,
+  queryPrefix?: string
+) => {
   return new Source({
     client: sparqlClient,
     queryOperation: "postUrlencoded",
-    queryPrefix: pragmas,
+    queryPrefix,
     sourceGraph: rdf.defaultGraph(),
   });
 };
diff --git a/app/rdf/queries.ts b/app/rdf/queries.ts
index 4e5e5e0f6..1f935c8f0 100644
--- a/app/rdf/queries.ts
+++ b/app/rdf/queries.ts
@@ -9,7 +9,7 @@ import { LRUCache } from "typescript-lru-cache";
 
 import { PromiseValue, truthy } from "@/domain/types";
 import { DataCubeComponentFilter } from "@/graphql/resolver-types";
-import { pragmas } from "@/rdf/create-source";
+import { createSource, pragmas } from "@/rdf/create-source";
 import { ExtendedCube } from "@/rdf/extended-cube";
 
 import { FilterValueMulti, Filters } from "../configurator";
@@ -610,6 +610,14 @@ export const getCubeObservations = async ({
     filters: observationFilters,
   });
 
+  // In order to fix an error with cartesian products introduced in preview query
+  // when using #pragma join.hash off, we need to have a clean source without
+  // decorating the sparql client. However we still need to keep the pragmas
+  // for the full query, to vastly improve performance.
+  observationsView.getMainSource = preview
+    ? () => createSource(sparqlClient)
+    : cubeView.getMainSource;
+
   const { query, observationsRaw } = await fetchViewObservations({
     preview,
     limit,
diff --git a/app/rdf/query-literals.ts b/app/rdf/query-literals.ts
index da8f09d34..a4d24c8de 100644
--- a/app/rdf/query-literals.ts
+++ b/app/rdf/query-literals.ts
@@ -1,6 +1,6 @@
 import { SELECT, sparql } from "@tpluscode/sparql-builder";
 import uniqBy from "lodash/uniqBy";
-import { NamedNode, Literal } from "rdf-js";
+import { Literal, NamedNode } from "rdf-js";
 import ParsingClient from "sparql-http-client/ParsingClient";
 import { LRUCache } from "typescript-lru-cache";
 
diff --git a/app/typings/rdf.d.ts b/app/typings/rdf.d.ts
index d62eaa34b..5a581bf4f 100644
--- a/app/typings/rdf.d.ts
+++ b/app/typings/rdf.d.ts
@@ -116,6 +116,7 @@ declare module "rdf-cube-view-query" {
     addDimension(dimension: Dimension): View;
     createDimension(options: $FixMe): Dimension;
     setDefaultColumns(): void;
+    getMainSource(): Source;
   }
 
   export type SourceOptions = NodeInit & {