Link to the code that reproduces this issue

https://codesandbox.io/p/live/f8229d08-1273-49bc-aefb-1063e88fa681

To Reproduce

Create a new API
Deploy on Vercel
Use new Date, and just return Date
Invoke it twice, and you're gone.

Current vs. Expected behavior

**EDIT: ** As soon as you purge the data it works. But this isn't even a solution.

I am using a webhook that registers users in my DB via prisma. Now For a trial period need to add month from current date. Such a simple task on vercel keeps on giving me past dates and the DB is updated with invalid subscription.

I have all this on top of my app router

export const dynamic = 'force-dynamic';
export const fetchCache = 'force-no-store';
export const revalidate = 0;

And even changed the code to this:

const startDate = moment().toDate();
        const endDate = moment(startDate).add(1, 'month').toDate();

Still no luck on vercel. Users can't be registered since a third party redirects to this webhook that registers the user.

Provide environment information

Operating System:
  Platform: win32
  Arch: x64
  Version: Windows 11 Home
  Available memory (MB): 16219
  Available CPU cores: 8
Binaries:
  Node: 21.5.0
  npm: 10.2.4
  Yarn: 1.22.22
  pnpm: 9.12.3
Relevant Packages:
  next: 15.1.7 // There is a newer version (15.3.1) available, upgrade recommended!     
  eslint-config-next: 15.1.7
  react: 19.0.0
  react-dom: 19.0.0
  typescript: 5.7.3
Next.js Config:
  output: N/A
 ⚠ There is a newer version (15.3.1) available, upgrade recommended!
   Please try the latest canary version (`npm install next@canary`) to confirm the issue still exists before creating a new issue.

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

Use Cache

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

Vercel (Deployed)

Additional context

No response