diff --git a/packages/ngtools/webpack/src/resource_loader.ts b/packages/ngtools/webpack/src/resource_loader.ts
index c7b8850c7e04..d494cdc930b2 100644
--- a/packages/ngtools/webpack/src/resource_loader.ts
+++ b/packages/ngtools/webpack/src/resource_loader.ts
@@ -274,12 +274,15 @@ export class WebpackResourceLoader {
 
           parent.warnings.push(...childCompilation.warnings);
           parent.errors.push(...childCompilation.errors);
-          for (const { info, name, source } of childCompilation.getAssets()) {
-            if (info.sourceFilename === undefined) {
-              throw new Error(`'${name}' asset info 'sourceFilename' is 'undefined'.`);
-            }
 
-            this.assetCache?.set(info.sourceFilename, { info, name, source });
+          if (this.assetCache) {
+            for (const { info, name, source } of childCompilation.getAssets()) {
+              // Use the originating file as the cache key if present
+              // Otherwise, generate a cache key based on the generated name
+              const cacheKey = info.sourceFilename ?? `!![GENERATED]:${name}`;
+
+              this.assetCache.set(cacheKey, { info, name, source });
+            }
           }
         }