Site fails to execute functions within a pnpm monorepo

[robations]

Describe the bug A clear and concise description of what the bug is.

Although static assets are served by netlify serve, no functions seem to be working and the index of the site (http://localhost:8888/) returns "404 Not Found".

To Reproduce Steps to reproduce the behavior:

1. Generate a new site npx create-remix@latest --template netlify/remix-template
2. (choosing functions, rather than edge)
3. Test the site working
4. Translocate site as a workspace within a pnpm monorepo:
   a. add missing dependencies (pnpm complains about react and react-dom missing)
   b. I had an issue with netlify-cli trying to run an unrelated workspace package (which also happens to have a netlify.toml file): added build.base: "packages/remix-netlify"
   c. tsconfigPaths was reporting errors in unrelated packages (added root parameter)
   d. Delete package-lock.json and node_modules
   e. Reinstall repo deps with pnpm i
5. Test the site within monorepo working correctly with remix vite:dev
6. netlify serve fails with 404 error at root of site and .netlify/functions-serve is missing (compared with original site)
7. Static client assets are served correctly (favicon.ico and CSS/JS under /assets/...)

Expected behavior A clear and concise description of what you expected to happen.

The site should work within a monorepo, or would expect some simple configuration to make it work.

Screenshots If applicable, add screenshots to help explain your problem.

Desktop (please complete the following information):

• OS: MacOS
• Browser: n/a
• Version: @netlify/remix-adapter: 2.5.1

Smartphone (please complete the following information):

• Device: n/a
• OS: n/a
• Browser n/a
• Version n/a

Additional context Add any other context about the problem here.

Can potentially create a new monorepo for testing if not easily reproducible.

It seems like part of the Netlify code is still mis-identifying a path, but it's not clear what or where.

[robations]

Notable difference:

.netlify within monorepo:

.netlify in isolated site:

[robations]

I've also just noticed that if I add build.base: "packages/remix-netlify" I get a spurious nested directory added within the workspace package:

Whereas without build.base, the netlify CLI gets very confused about paths (tries to build within packages/foo even though it is filtered to packages/remix-netlify).

For context, I have something like 15 other netlify sites working correctly within this repo.