fix: redirect isr index pages without a sub path

Author: orinokai

packages/runtime/src/helpers/redirects.ts

@@ -143,8 +143,8 @@ const generateStaticIsrRewrites = ({
       return
     }
     // The default locale is served from the root, not the localised path
-    if (i18n?.defaultLocale && route.startsWith(`/${i18n.defaultLocale}/`)) {
-      route = route.slice(i18n.defaultLocale.length + 1)
+    if (i18n?.defaultLocale && route.startsWith(`/${i18n.defaultLocale}`)) {
+      route = route.slice(i18n.defaultLocale.length + 1) || '/'
       staticRoutePaths.add(route)
       if (matchesMiddleware(middleware, route)) {
         staticIsrRoutesThatMatchMiddleware.push(route)