Parallel Route with Slug makes page render twice

[canopy-cj]

Link to the code that reproduces this issue

https://github.com/canopy-cj/Nextjs-Parallel-Route-Issue

To Reproduce

1. Run build (npm run build) and start (npm run start)
2. Navigate to main page (http:localhost:3000). You should see Pokemon List page is rendered once.
3. Click on one of pokemon. You should see Pokemon page is rendered twice.

Current vs. Expected behavior

Screen.Recording.2025-01-13.at.3.13.36.PM.mov

Current

This happens when I add [slug] inside parallel route (breadcrumb) which makes page to render twice if I navigate to same path as slug. This impacts the fetch/database call in the Page to call twice.

The breadcrumb implementation is followed by this example.

Expected

I want the page to render once such that fetch/database call to be only called once.

Provide environment information

Operating System:
  Platform: darwin
  Arch: arm64
  Version: Darwin Kernel Version 23.6.0: Fri Nov 15 15:12:37 PST 2024; root:xnu-10063.141.1.702.7~1/RELEASE_ARM64_T6030
  Available memory (MB): 36864
  Available CPU cores: 12
Binaries:
  Node: 20.12.2
  npm: 10.5.0
  Yarn: N/A
  pnpm: N/A
Relevant Packages:
  next: 15.1.4 // Latest available version is detected (15.1.4).
  eslint-config-next: 15.1.4
  react: 19.0.0
  react-dom: 19.0.0
  typescript: 5.7.3
Next.js Config:
  output: N/A

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

Performance, Parallel & Intercepting Routes

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

next start (local)

Additional context

No response