Metadata not showing up in dev mode for not-found.tsx page

### Link to the code that reproduces this issue https://github.com/dmorda/not-found-example ### To Reproduce 1. `git clone https://github.com/dmorda/not-found-example` 2. `cd not-found-example` 3. `npm install` 4. `npm run dev` 5. Visit http://localhost:3000/abc123 ### Current vs. Expected behavior I expect the the title and meta description to be: title: Page Not Found meta-description: The page you are looking for does not exist. The actual title and meta description are: title: Create Next App meta-description: Generated by create next app If you remove the catch all route (i.e., [...slug]) folder and visit the same page, it will display: title: Page Not Found meta-description: The page you are looking for does not exist. ### Provide environment information ```bash Operating System: Platform: darwin Arch: arm64 Version: Darwin Kernel Version 24.3.0: Thu Jan 2 20:24:22 PST 2025; root:xnu-11215.81.4~3/RELEASE_ARM64_T6041 Available memory (MB): 49152 Available CPU cores: 14 Binaries: Node: 22.14.0 npm: 11.1.0 Yarn: 1.22.22 pnpm: N/A Relevant Packages: next: 15.2.1 // Latest available version is detected (15.2.1). eslint-config-next: 15.2.1 react: 19.0.0 react-dom: 19.0.0 typescript: 5.8.2 Next.js Config: output: N/A ``` ### Which area(s) are affected? (Select all that apply) Metadata, Dynamic Routes ### Which stage(s) are affected? (Select all that apply) next dev (local) ### Additional context The behavior seemed to change between 15.1.7 (was working as expected) to 15.2.1 (stopped working as expected). It also only seems to happen in local development mode. If I build and deploy to Vercel, the same path produces the expected result containing the correct title and meta-description.