diff --git a/packages/next/src/server/patch-error-inspect.ts b/packages/next/src/server/patch-error-inspect.ts
index a89ed1bde88d8..6d85dd186cbb0 100644
--- a/packages/next/src/server/patch-error-inspect.ts
+++ b/packages/next/src/server/patch-error-inspect.ts
@@ -157,7 +157,7 @@ function parseAndSourceMap(error: Error): string {
         if (
           process.env.NODE_ENV !== 'production' &&
           sourcemappedFrame.code !== null &&
-          sourceFrameDEV !== null
+          sourceFrameDEV === null
         ) {
           sourceFrameDEV = sourcemappedFrame.code
         }