Link to the code that reproduces this issue

https://github.com/matthewwilson/nextjs-boilerplate

To Reproduce

1. Deploy the application to Vercel.

It consists of 3 pages

• Home Page (static)
• Child Page (static)
• Edge Page (edge)

All pages make the same API call.

2. During the build process observe the outputted timestamps returned from the API

A healthy output should look like this:

Got timestamp 1698315066.387
Got timestamp 1698315066.387
Got timestamp 1698315066.387
Got timestamp 1698315066.387

In this scenario everything will revalidate as expected by POSTing to the revalidate endpoint (/api/revalidate).

This is unhealthy output:

Got timestamp 1698315066.387
Got timestamp 1698315066.387
Got timestamp 1698315070.085
Got timestamp 1698315070.09

As soon as we start getting different timestamps (meaning that the API call isn't being memoized/cached) then revalidateTag will only revalidate one of the pages (home or child). No matter how many times revalidateTag is called, only one page will update.

Current vs. Expected behavior

I expect revalidateTag to work reliably when revalidating an API call that is used across multiple pages.

The sample app here is a simple reproduction, but we are seeing this same issue in production.

Removing the edge page fixes the issue. But this is not an option for us.

Everything works when running locally, but breaks on Vercel.

Verify canary release

• I verified that the issue exists in the latest Next.js canary release

Provide environment information

Operating System:
  Platform: darwin
  Arch: arm64
  Version: Darwin Kernel Version 22.6.0: Fri Sep 15 13:41:28 PDT 2023; root:xnu-8796.141.3.700.8~1/RELEASE_ARM64_T6000
Binaries:
  Node: 18.18.0
  npm: 9.8.1
  Yarn: 1.22.19
  pnpm: 8.8.0
Relevant Packages:
  next: 13.5.7-canary.35
  eslint-config-next: 13.5.4
  react: 18.2.0
  react-dom: 18.2.0
  typescript: 5.2.2
Next.js Config:
  output: N/A

Which area(s) are affected? (Select all that apply)

Data fetching (gS(S)P, getInitialProps)

Additional context

This issue has existed across multiple Next.js versions.

We have tested it from 13.4.13 to 13.5.7-canary.35