--prod flag ignored when running `netlify deploy --build`

[joepio]

Describe the bug

netlify deploy --build -s arguco --prod

To Reproduce

Steps to reproduce the behavior:

1. Fork the repository https://github.com/ontola/atomic-argu/
2. Deploy it to Netlify netlify deploy --build -s arguco --prod
3. In the logs: Skip submitting sitemap to google, yandex, because this isn't a production build
4. See that the sitemap file is missing...

However, if we run seperate steps:

1. netlify build
2. sitemap.xml is in the build dir!
3. netlify deploy --prod
4. Yay it's live!

Additional context

• netlify 13.1.10