While minifying app stylesheet: app/client/main.css Unknown word

Hi, I’m new to Meteor and Javascript so here goes… Recently rolled back my Mac to previous timemachined state due to bug. Updated a few things and relaunched meteor app project but now see a new bug which is blocking the app load: While minifying the app stylesheet app/client/main.css: Unknown word. I presume I need to update/rollback or install something. Google hasn’t been much help. I tried removing Standard CSS minifier from the project. The app now loads with different console bugs and no content so that hasn’t fixed the issue but seems related to Standard CSS minifier. I’d like to understand what is causing this error.