high85%
Next.js 16.2.x regression: sitemap.xml route handler with dynamic segments fails to register on Vercel due to parallel build race
A route handler at [store]/[lang]/c/sitemap.xml with force-static fails the build with 'Invariant: failed to find source route', while with dynamic='auto' the route is not registered and requests are incorrectly matched to a sibling [slug] route. The issue is reproducible only on Vercel with parallel build workers, indicating a race condition in app output map registration. Renaming the sitemap.xml folder or using a non-sitemap.xml name avoids the bug.