Astro endpoints execute correctly but return 500 if built with pnpm

[jimpala]

Question

Hello,

I have an Astro project for which I'm using pnpm, set to server (SSR) mode, with one POST endpoint.

If Vercel is set to build and run the project using pnpm, these endpoint functions execute, but fail to send a 200 response at the end with the associated error logs:

TypeError: NodeApp.writeResponse is not a function
    at Server.handler (file:///var/task/vercel/path0/.vercel/output/_functions/entry.mjs:1984:19)
    at process.processTicksAndRejections (node:internal/process/task_queues:95:5)
    at async Server.<anonymous> (/opt/node-bridge/bridge-server-BGIDXK2J.js:1:9443)

If the project is instead built and run with npm, this issue doesn't occur and a 200 is correctly returned.