ts-loader: 2.2.1 = npm error "Could not find file:" ...

Just started getting this npm build error with 2.2.1, not a ton of other details I can find yet.

./node_modules/typescript/lib/typescript.js:89078
throw new Error("Could not find file: '" + fileName + "'.");

using it like this

 loaders: [{
      test: /\.ts(x?)$/,
      exclude: /node_modules/,
      use: [
        {
          loader: 'babel-loader',
          options: {
            presets: [['es2015'], 'stage-0', 'react'].concat(DEBUG ? ['react-hmre'] : []),
          },
        },
        {
          loader: 'ts-loader',
        },
      ],
    },

If I revert to 2.2.0, everything works fine. Using Typescript 2.4.1, NPM 5.0.3 on macOs