diff --git a/bundles/EcommerceFrameworkBundle/IndexService/ProductList/ElasticSearch/AbstractElasticSearch.php b/bundles/EcommerceFrameworkBundle/IndexService/ProductList/ElasticSearch/AbstractElasticSearch.php
index 83c9b1421d7..c33114e026f 100644
--- a/bundles/EcommerceFrameworkBundle/IndexService/ProductList/ElasticSearch/AbstractElasticSearch.php
+++ b/bundles/EcommerceFrameworkBundle/IndexService/ProductList/ElasticSearch/AbstractElasticSearch.php
@@ -1268,7 +1268,7 @@ protected function convertBucketValues(array $bucket)
                 $data['key_as_string'] = $bucket['key_as_string'];
             } elseif (is_array($reverseAggregationBucket) && array_key_exists('doc_count', $reverseAggregationBucket)) { // reverse aggregation
                 $data['reverse_count'] = $reverseAggregationBucket['doc_count'];
-            } elseif (is_array($subAggregationBuckets['buckets'])) {        // sub aggregations
+            } elseif (is_array($subAggregationBuckets) && isset($subAggregationBuckets['buckets'])) {         // sub aggregations
                 foreach ($subAggregationBuckets['buckets'] as $bucket) {
                     $data[$subAggregationField][] = $this->convertBucketValues($bucket);
                 }