Failing actions deployment since Vue upgrade

I’ve just started getting the following error in my actions deployment. I get no such errors on my personal machine running up to date Ubuntu 20.04 & Node v14, the build compiles fine. I am running a beta of VUE CLI Service that apparently uses Webpack 5 (~5.0.0-beta.2) behind the scenes, should I take it up with them? Or might it be an issue in the actions environment? I’m not sure what to try next to narrow it down / diagnose it.

> vue-cli-service build

-  Building legacy bundle for production...

(node:1978) [DEP_WEBPACK_COMPILATION_NORMAL_MODULE_LOADER_HOOK] DeprecationWarning: Compilation.hooks.normalModuleLoader was moved to NormalModule.getCompilationHooks(compilation).loader
(Use `node --trace-deprecation ...` to show where the warning was created)
 ERROR  Failed to compile with 1 error12:02:16 PM

 error  in css/app.19d26c7c.css

css/app.19d26c7c.css from Css Minimizer
Error: PostCSS plugin postcss-discard-comments requires PostCSS 8.
Migration guide for end-users:
 ERROR  Error: Build failed with errors.
    at Processor.normalize... <snipped for brevity's sake>