App breaks when route params contain pipe character(i.e "|") #6288

Which project does this relate to?

Start

Describe the bug

I am facing a bug where pipe symbol i.e "|" breaks app when navigating to a dynamic route that contains the symbol as param, e.g a string like "ER|2024FHTd"

This seems to only be happening in tanstack start, not router.

You can navigate to the route via link without Breaking how ever, if you reload page afterwards or try to navigate directly to it, app breaks

Your Example Website or App

https://tanstack-start-param-issue.vercel.app/

Steps to Reproduce the Bug or Issue

1. Create a dynamic route in tanstack start app e.g $reference.tsx
2. Create a link or button that navigates to /$reference with a pipe symbol in the param value
3. Navigate to route via link/button - navigation works,
4. Reload page after navigation or navigate directly to the page by entering the url - app breaks, shows ERR_TOO_MANY_REDIRECTS

Expected behavior

Route should not break when navigating to a dynamic route with pipe

Screenshots or Videos

Platform

• Start Version: [e.g. 1.121.0]
• macOS
• Browser: Chrome
• Browser Version: 143.0.7499.170
• Bundler: vite
• Bundler Version: 7.1.7

Additional context

No response