--- a/toolkit/components/url-classifier/nsUrlClassifierDBService.cpp
+++ b/toolkit/components/url-classifier/nsUrlClassifierDBService.cpp
@@ -899,19 +899,21 @@ nsUrlClassifierDBServiceWorker::CacheCom
       updates.AppendElement(tu);
       pParse->ForgetTableUpdates();
     } else {
       LOG(("Completion received, but table %s is not active, so not caching.",
            result->table.get()));
     }
    }
 
-  mClassifier->ApplyFullHashes(&updates);
-  mLastResults = std::move(resultsPtr);
-  return NS_OK;
+  rv = mClassifier->ApplyFullHashes(&updates);
+  if (NS_SUCCEEDED(rv)) {
+    mLastResults = std::move(resultsPtr);
+  }
+  return rv;
 }
 
 nsresult
 nsUrlClassifierDBServiceWorker::CacheResultToTableUpdate(CacheResult* aCacheResult,
                                                          TableUpdate* aUpdate)
 {
   auto tuV2 = TableUpdate::Cast<TableUpdateV2>(aUpdate);
   if (tuV2) {