Locally stored libaries from cdnjs in Pug mixin not being recognized

I have corejs and a classlist polyfill being imported from a Pug mixin into every page of a static website. When IntelliJ prompts me to download them into a local library, it says "Succesfully downloaded ..." and the library shows up in External Libraries, but the script tags remain in yellow and it still prompts to download it again. How do I tell IntelliJ that the libraries correspond to the script tags? I'm using Gulp to build the website from a src folder to an output folder if it matters.

mixin header(title)
    head
        meta(charset='utf-8')
        meta(name='viewport' content='width=device-width, initial-scale=1')
        link(rel='icon' href='images/icon-html.svg')
        link(rel='stylesheet' href='style.css')
        title= title
        script(src="https://cdnjs.cloudflare.com/ajax/libs/core-js/3.21.1/minified.min.js")
        script(src="https://cdnjs.cloudflare.com/ajax/libs/classlist/1.2.20171210/classList.min.js")
        block