diff --git a/lib/optimize/ConcatenatedModule.js b/lib/optimize/ConcatenatedModule.js
index f388705d9d6..4440a6acbb2 100644
--- a/lib/optimize/ConcatenatedModule.js
+++ b/lib/optimize/ConcatenatedModule.js
@@ -214,7 +214,9 @@ class ConcatenatedModule extends Module {
 	}
 
 	get modules() {
-		return this._orderedConcatenationList.map(m => m.module);
+		return this._orderedConcatenationList
+			.filter(info => info.type === "concatenated")
+			.map(info => info.module);
 	}
 
 	identifier() {