diff --git a/build/azure-pipelines/mixin.js b/build/azure-pipelines/mixin.js
index 203727861e..87809d2fe9 100644
--- a/build/azure-pipelines/mixin.js
+++ b/build/azure-pipelines/mixin.js
@@ -55,7 +55,7 @@ function main() {
 				fancyLog(ansiColors.blue('[mixin]'), 'Inheriting OSS built-in extensions', builtInExtensions.map(e => e.name));
 			}
 
-			return { ...o, builtInExtensions };
+			return { ...ossProduct, ...o, builtInExtensions };
 		}))
 		.pipe(productJsonFilter.restore)
 		.pipe(es.mapSync(function (f) {