diff --git a/lib/cache/FileCachePlugin.js b/lib/cache/FileCachePlugin.js
index <HASH>..<HASH> 100644
--- a/lib/cache/FileCachePlugin.js
+++ b/lib/cache/FileCachePlugin.js
@@ -173,7 +173,7 @@ class FileCachePlugin {
 			(identifier, etag, data) => {
 				const entry = {
 					identifier,
-					data: store === "pack" ? data : () => data,
+					data: etag ? () => data : data,
 					etag,
 					version
 				};
use lazy serialization when etag is passed