Error filestem is not defined after initial npm install and run

[xdcha]

Hello. <3 the boilerplate, however, on npm start for the first time I am hit with an error:

file:///Volumes/e/build/tasks/styles.js:234
    const timeLabel = `${filestem}.css purged in`;
                      ^

ReferenceError: filestem is not defined
    at purgeUnusedCSS (file:///Volumes/e/build/tasks/styles.js:234:23)
    at file:///Volumes/e/build/tasks/styles.js:149:25
    at async file:///Volumes/e/build/tasks/styles.js:146:17

Many thanks

[mcaskill]

Thanks