diff --git a/packages/gitbook/src/middleware.ts b/packages/gitbook/src/middleware.ts
index 8a75df506..e346b9c8f 100644
--- a/packages/gitbook/src/middleware.ts
+++ b/packages/gitbook/src/middleware.ts
@@ -496,7 +496,9 @@ async function serveSiteRoutes(requestURL: URL, request: NextRequest) {
                     themeMode === CustomizationThemeMode.Dark
                         ? CustomizationDefaultThemeMode.Dark
                         : CustomizationDefaultThemeMode.Light;
-            } else {
+            } else if (routeTypeFromPathname !== 'static') {
+                // Markdown, llms.txt, RSS and sitemap routes only exist under `sites/static`, so
+                // forcing them dynamic 404s. They don't render a theme anyway. RND-12749.
                 routeType = 'dynamic';
                 requestHeaders.set(MiddlewareHeaders.Theme, themeMode);
             }