diff --git a/lib/core/middleware/error.js b/lib/core/middleware/error.js
index d219db5881..52e2603ea6 100644
--- a/lib/core/middleware/error.js
+++ b/lib/core/middleware/error.js
@@ -102,7 +102,8 @@ async function readSource(frame) {
   }
 
   // Fallback: use server bundle
-  /* istanbul ignore if */
+  // TODO: restore to if after https://github.com/istanbuljs/nyc/issues/595 fixed
+  /* istanbul ignore next */
   if (!frame.contents) {
     frame.contents = this.resources.serverBundle.files[frame.fileName]
   }