[TypeScript] Does not work with project references

I try to deploy one of my TypeScript projects to ZEIT Now and get a lot of Module build failed (from (webpack)/ncc/loaders/ts-loader.js): errors.

Could it be that I'm getting these errors because I'm using project references? Or is this somehow related to #291?

My tsconfig.json file looks like this:

{
  "files": [],
  "references": [
    { "path": "./src/one" },
    { "path": "./src/two" },
    { "path": "./test/unit/one" },
    { "path": "./test/unit/two" }
  ]
}

(every of these directories contain a separate tsconfig.json with composite set to true).

I'm not sure if this is related to zeit/now-builders or to ncc 🤔

Start with the reported tsconfig.json and TypeScript project-references documentation, then reproduce the deployment errors in the described ZEIT Now setup. Compare whether the failure comes from ncc or zeit/now-builders, including the context from issue #291; done means the source of the errors is identified and project references either work or are clearly documented as unsupported.