diff --git a/plugins/catalog-backend/src/service/createRouter.ts b/plugins/catalog-backend/src/service/createRouter.ts
index 84826267f2..601b0b1098 100644
--- a/plugins/catalog-backend/src/service/createRouter.ts
+++ b/plugins/catalog-backend/src/service/createRouter.ts
@@ -216,7 +216,7 @@ export async function createRouter(
               signal.throwIfAborted();
 
               if (!disableRelationsCompatibility) {
-                processEntitiesResponseItems(
+                result.items = processEntitiesResponseItems(
                   result.items,
                   expandLegacyCompoundRelationsInEntity,
                 );
diff --git a/plugins/catalog-backend/src/service/response/process.ts b/plugins/catalog-backend/src/service/response/process.ts
index 7e7730d697..fa07063f5b 100644
--- a/plugins/catalog-backend/src/service/response/process.ts
+++ b/plugins/catalog-backend/src/service/response/process.ts
@@ -39,7 +39,7 @@ export function processRawEntitiesResult(
 export function processEntitiesResponseItems(
   response: EntitiesResponseItems,
   transform?: (entity: Entity) => Entity,
-) {
+): EntitiesResponseItems {
   if (!transform) {
     return response;
   }