diff --git a/build/azure-pipelines/distro/mixin-quality.ts b/build/azure-pipelines/distro/mixin-quality.ts
index c8ed6886b79..d1cc9c92b12 100644
--- a/build/azure-pipelines/distro/mixin-quality.ts
+++ b/build/azure-pipelines/distro/mixin-quality.ts
@@ -48,9 +48,8 @@ function main() {
 			let builtInExtensions = oss.builtInExtensions;
 
 			if (Array.isArray(distro.builtInExtensions)) {
-				log('Overwriting built-in extensions:', distro.builtInExtensions.map(e => e.name));
+				throw new Error('Unexpected builtInExtensions array, expected object with include/exclude or array of extensions');
 
-				builtInExtensions = distro.builtInExtensions;
 			} else if (distro.builtInExtensions) {
 				const include = distro.builtInExtensions['include'] ?? [];
 				const exclude = distro.builtInExtensions['exclude'] ?? [];