Tengo un proyecto que funciona bien cuando ejecuto npm start pero falla con este error cuando ejecuto npm run build o yarn build

 Failed to compile. Cannot read property 'toLowerCase' of undefined CompileError: Begins at CSS selector .invert-color .form-checkbox input:checked,.invert-color .form-radio input:checked npm ERR! code ELIFECYCLE npm ERR! errno 1 npm ERR! open-react-template@0.1.0 build: `react-scripts build` npm ERR! Exit status 1 npm ERR! npm ERR! Failed at the open-react-template@0.1.0 build script. npm ERR! This is probably not a problem with npm. There is likely additional logging output above. ...