Another fix here: Deploy failed today: Build was terminated: Build script returned non-zero exit code: 1 - #4 by nathanmartin
You can set npm flags in Netlify to build using —force or —legacy-peer-deps. Even if your package-lock file was built using one of those flags, they seem to be broken or ignored by Netlify with 16.15.1.
EDIT: Node introduced this error by changing the way the npm ci command builds sites with 16.15.1. Read more on their github issues page.