I'm seeing inconsistent cache invalidation behavior between local builds and Vercel when using Cache Components with use cache + cacheTag in Next.js 16.1.Architecture

- App Router
- Cache Components
- Home page renders 10 product cards
- Each card includes cached server components
- Product editing happens in a parallel route sidebar

Route structure:

/page
/@sidebar/(.)edit/[productId]

The sidebar allows editing a product while the home page remains visible.

Cached component

One of the components inside the product card looks like this:

export async function ProductDescription({ id }: { id: number }) {
  "use cache";
  cacheTag(`description-${id}`);

  const productData = await getProduct(id);
  if (!productData) return null;

  const { description } = productData;
  const date = new Date();

  return (
    <UpdateHighlight updatedAt={date}>
      <p className="text-sm leading-relaxed text-muted-foreground">
        {description}
      </p>
    </UpdateHighlight>
  );
}

Invalidation

After editing the product I call:

updateTag(`description-${id}`)

Observed behavior

Local (dev + local production build)

- updateTag works
- The component re-renders
- My overlay showing the last server render timestamp updates

Vercel

- updateTag runs
- Cached fields like description do not update
- However dynamic fields (like stock) that are not cached update correctly

This suggests the "use cache" component tagged with cacheTag is not being invalidated on Vercel.

Question

Is there any difference in how updateTag works with the Vercel Data Cache vs local builds when using "use cache" components?

Could parallel routes or RSC boundaries affect tag invalidation in production?

Environment

Next.js: 16.1
Deployment: Vercel
Runtime: Bun
Node compatibility: Bun runtime