[BUG] Page redirect applies the target route twice and mangles the URL

[SDrinkwater]

Describe the bug

Calling redirect on page load results in the target route being added twice to the URL.

Example:

• I have two pages
  • Home which lives at / and simply returns redirect("/target");
  • Target which lives at /target and returns <div>Target</div>;

Expected behaviour (and the behaviour I see when running via npm run dev):

Loading the / route takes me to /target

Observed behaviour:

Loading the / route takes me to /target,/target

Steps to reproduce

• Create two pages
  • Home which lives at / and simply returns redirect("/target");
  • Target which lives at /target and returns <div>Target</div>;

Now load the / route and notice that it takes you to /target,/target.

Expected behavior

Redirecting on page load takes me to the target page.

Keeping with our example, this means:

Loading the / route takes me to /target

@opennextjs/cloudflare version

1.7.1

Wrangler version

4.34.0

next info output

Using vars defined in .dev.vars
/bin/sh: yarn: command not found

Operating System:
  Platform: darwin
  Arch: arm64
  Version: Darwin Kernel Version 24.6.0: Mon Jul 14 11:30:55 PDT 2025; root:xnu-11417.140.69~1/RELEASE_ARM64_T6031
  Available memory (MB): 36864
  Available CPU cores: 14
Binaries:
  Node: 22.13.1
  npm: 11.1.0
  Yarn: N/A
  pnpm: 9.15.1
Relevant Packages:
  next: 15.4.6 // There is a newer version (15.5.2) available, upgrade recommended! 
  eslint-config-next: 15.4.6
  react: 19.1.0
  react-dom: 19.1.0
  typescript: 5.9.2
Next.js Config:
  output: N/A
 ⚠ There is a newer version (15.5.2) available, upgrade recommended! 
   Please try the latest canary version (`npm install next@canary`) to confirm the issue still exists before creating a new issue.
   Read more - https://nextjs.org/docs/messages/opening-an-issue

Additional context

No response

[vicb]

@SDrinkwater 2 things:

• please try with 1.6.5 and report if it has the same behavior?
• please add a repro (link to a GH repository) so that we can be sure we are looking at the same thing.
  Thanks

[SDrinkwater]

@vicb Thanks for the speedy reply!

I just gave 1.6.5 a go and I'm seeing the same issue. Here's a repo with the above setup: https://github.com/SDrinkwater/redirect-repro.

Looks like this is a similar issue to opennextjs/opennextjs-aws#962 and vercel/next.js#83057.

[vicb]

Looks like this is a similar issue to opennextjs/opennextjs-aws#962 and vercel/next.js#83057.

What is the behavior of npm run start (you mention an issue in vercel/next.js, the problem might be there?)

[sommeeeer]

Can you try setting an incrementalCache ? Is the problem still there then? https://opennext.js.org/cloudflare/caching#incremental-static-regeneration-isr

[vicb]

I took a quick look at your repro, this confirms your findings:

• npm run dev works as expected (redirect to /target)
• npm run preview redirect to /target,/target

So the issue seems to be on the Cloudflare side

[sommeeeer]

@SDrinkwater Did you see my comment? Having an incrementalCache should resolve this problem.

Turns out this is a Next problem under the hood. They return a Location header which is an array on the response headers if you build in standalone mode without a successful async get in the cacheHandler. In next start or node .next/standalone/server.js that array would turn into two Location headers:

The reason its comma seperated in OpenNext is these lines of code. Im not sure what to do about that. Should we perhaps fix this on our side? WDYT @conico974. We could potentially just skip that function if its Location. Anyhow, for now just add an incrementalCache to resolve your problem.

To reproduce this in next start (this will mimic not having incrementalCache in OpenNext) just have this as your next config:

const nextConfig: NextConfig = {
  cacheHandler: require.resolve("./cache-handler.js"),
  output: "standalone"
};

Then in have a ./cache-handler.js file with this contents:

export default class {
  async get(key, cacheType) {
    return null;
  }
}

Now just run npm run build && npm run start (or node .next/standalone/server.js) and see multiple Location headers

[avernikoz]

Happening for me as well.
Downgrading to nextjs 15.2.3 and opennextjs 1.6.5 solved my problem.

[sommeeeer]

Happening for me as well. Downgrading to nextjs 15.2.3 and opennextjs 1.6.5 solved my problem.

Do you have an incrementalCache configured in your open-next.config.ts?

[avernikoz]

Happening for me as well. Downgrading to nextjs 15.2.3 and opennextjs 1.6.5 solved my problem.

Do you have an incrementalCache configured in your open-next.config.ts?

No, I don't. Honestly, I'd prefer a more general solutions, as configuring cache, especially just to fix different problem sounds too harsh for me, since it require to dive into what's the best caching strategy to apply for an app.
I understand that the problem is somewhere in next.js, and appreciate sharing the workaround

Curious to know — does cache configuration you've suggest require app to use it anyhow?
Or just configuring cache solves the problem entirely, while doesn't force to use it in any way?

[avernikoz]

Turns out I couldn't use 15.2.3 next.js version, need 15.4.1+, so, I've set up incrementalCache and it worked.
cc: @sommeeeer

[sommeeeer]

This problem only happens when you dont have an incrementalCache. That PR that is linked to this issue will also make sure to not merge Location header if its duplicated (i.e Next returns an array).