Immutable headers error when using a shared client SDK inside of a monorepo #6636
Description
Which project does this relate to?
Start
Describe the bug
I'm receiving an Immutable Headers error when trying to use a shared SDK client in a bun monorepo. I have to use < v1.139 of the tanstack router NPM package. I'm not entirely sure what changed between 1.139 and 1.140 that caused the headers to be immutable, but it's something to look at.
Your Example Website or App
n/a
Steps to Reproduce the Bug or Issue
Hardcoded v1.139 of @tanstack/react-router and everything works as expected. As soon as I allow a package version greater 1.139, I get the immutable headers error. No other packages change.
Expected behavior
I expect to be able to interact with the headers just like I am able to in < v1.139 package versions.
Screenshots or Videos
No response
Platform
- Router / Start Version: [e.g. 1.159.5]
- OS: macOS
- Browser: Chrome, Safari, Firefox
- Bundler: vite
- Bundler Version: 7.1.7
Additional context
No response