CSS sourcemaps with bud?

I tried eval as a string, and it returned an error stating devtool requires a boolean option.

Module build failed (from ./node_modules/css-loader/dist/cjs.js):                                                        │
│ ValidationError: Invalid options object. CSS Loader has been initialized using an options object that does not match the │
│ API schema.                                                                                                              │
│ - options.sourceMap should be a boolean.                                                                                 │
│ -> Allows to enable/disable source maps.                                                                                 │
│ -> Read more at https://github.com/webpack-contrib/css-loader#sourcemap    

I also read the bud docs and it shows by example:



Looking at .budfiles/bud/webpack.config.js , I see sourcemap is set to true , and if I specify something like bud.devtool('eval-source-map'), I can see the option reflected within .budfiles/bud/webpack.config.js but I still get the CLI error as posted above and no sourcemap.