I got two packages in my turborepo, backend and frontend. I've set the root directory to be packages/frontend in Vercel Project Settings. I expect only the frontend to build but the backend is also built. What information will you need from to help me find out why that is?

Despite the backend being built as well, the frontend artifact is correctly published and deployed. It's just that I can't figure out why the backend is built as well.

Here is the first few lines of the deployment log:

Running build in Washington, D.C., USA (East) – iad1
Cloning github.com/hornta/crm (Branch: master, Commit: 6df7582)
Cloning completed: 461.573ms
Skipping build cache since Node.js version changed from "18.x" to "20.x"
Running "vercel build"
Vercel CLI 33.6.2
WARN! Missing required `build` pipeline in turbo.json or package.json Turbo configuration. Skipping automatic setting assignment.
Detected `pnpm-lock.yaml` version 6 generated by pnpm 8
Installing dependencies...
Scope: all 5 workspace projects