Adding FullCalendar to React on Rails project causes DoubleLinkError in application.css

Question

I have a React project served using Ruby on Rails 7. It's set up using this tutorial (source code available here); I'm at the part where you add React Router so you can add a second page to the app.

I ran yarn add @fullcalendar/react @fullcalendar/daygrid and created a new component:

import React from 'react';
import FullCalendar from '@fullcalendar/react';
import dayGridPlugin from '@fullcalendar/daygrid';

const Hoard = () => {
    return <div>
        <FullCalendar
            plugins={[ dayGridPlugin ]}
            initialView="dayGridMonth"
        />
    </div>
}

export default Hoard;

Then when I run ./bin/dev and load the page, I get this error:

It seems that FullCalendar's CSS is somehow breaking Rails' asset pipeline. That doesn't make sense to me; FullCalendar doesn't have a file named application.css. Rails is creating app/assets/builds/application.css and then complaining that its filename conflicts with app/assets/stylesheets/application.css. This seems like a Rails problem instead of a FullCalendar problem, but it didn't come up until I added FullCalendar to the project. I can fix the problem by uninstalling FullCalendar, deleting my @node_modules folder, running rake assets:clobber and then rake assets:precompile.

Is this a FullCalendar problem or a Rails problem?