From https://github.com/babel/babel/issues/8754: > Compilation of `node_modules` is becoming more common as more packages are publish as ES6. > > This is causing problems in two ways: > > * `transform-runtime` can potentially insert references to `core-js` into `core-js` itself > * `transform-runtime` can potentially insert references to `@babel/runtime-corejs2` into `core-js` itself > * `transform-runtime` can potentially insert references to `@babel/runtime-corejs2` into _itself_, causing dependency cycles > * And similar with `useBuiltins: 'usage'` transforming `core-js`. > [...] I think the same question needs to be discussed here.