为什么404.html在服务工作者缓存期间导致未捕获的错误？

我在Web应用程序中实现了service worker，并尝试缓存所有html，css，js和图像文件。我的托管服务是firebase，在成功部署后，我测试了该服务是否可以正常工作以及文件是否将被缓存，不幸的是会发生以下错误。

service-worker.js

let cacheName = 'my-tools-v1';
let filesToCache = [
    '/',
    '/css/app.css',
    '/css/diffview.css',
    '/css/json-lint.css',
    '/css/materialize.css',
    '/images/favicon.png',
    '/images/icons/apple-touch-icon.png',
    '/images/icons/apple-touch-icon-57x57.png',
    '/images/icons/apple-touch-icon-72x72.png',
    '/images/icons/apple-touch-icon-76x76.png',
    '/images/icons/apple-touch-icon-114x114.png',
    '/images/icons/apple-touch-icon-120x120.png',
    '/images/icons/apple-touch-icon-144x144.png',
    '/images/icons/apple-touch-icon-152x152.png',
    '/images/icons/apple-touch-icon-180x180.png',
    '/images/icons/icon-72x72.png',
    '/images/icons/icon-96x96.png',
    '/images/icons/icon-128x128.png',
    '/images/icons/icon-144x144.png',
    '/images/icons/icon-152x152.png',
    '/images/icons/icon-192x192.png',
    '/images/icons/icon-384x384.png',
    '/images/icons/icon-512x512.png',
    '/js/index.js',
    '/js/css-lint.js',
    '/js/difflib.js',
    '/js/diffview.js',
    '/js/ipsum-generator.js',
    '/js/json2.js',
    '/js/json-lint.js',
    '/js/jsonlint.js',
    '/js/lorem-ipsum.js',
    '/js/materialize.js',
    '/js/visual-difference.js',
    '/bower_components/codemirror/lib/codemirror.js',
    '/bower_components/codemirror/mode/javascript/javascript.js',
    '/bower_components/codemirror/mode/css/css.js',
    '/bower_components/codemirror/addon/edit/matchbrackets.js',
    '/bower_components/codemirror/addon/comment/continuecomment.js',
    '/bower_components/codemirror/addon/comment/comment.js',
    '/bower_components/ft-csslint/dist/csslint.js',
    '/bower_components/jquery/dist/jquery.slim.min.js',
    '/bower_components/kanye-ipsum/dist/jquery.kanye-ipsum.min.js',
    '/bower_components/codemirror/lib/codemirror.css',
    '/index.html',
    '/css-lint.html',
    '/ipsum-generator.html',
    '/json-lint.html',
    '/visual-difference.html',
    '/notfound.html',
    '/404.html'
];

self.addEventListener('install', (e) => {
    console.log('[ServiceWorker] Install');

    e.waitUntil(
        caches.open(cacheName).then((cache) => {
            console.log('[ServiceWorker] Caching app shell');
            return cache.addAll(filesToCache);
        })
    );
});

self.addEventListener('activate', (e) => {
    console.log('[ServiceWorker] Activate');

    e.waitUntil(
        caches.keys().then(function(keyList) {
            return Promise.all(keyList.map((key) => {
                if (key !== cacheName) {
                    console.log('[ServiceWorker] Removing old cache', key);
                    return caches.delete(key);
                }
            }));
        })
    );
});

self.addEventListener('fetch', (e) => {
    console.log('[ServiceWorker] Fetch', e.request.url);

    e.respondWith(
        caches.match(e.request).then((response) => {
            return response || fetch(e.request);
        })
    );
});

然后，因此没有缓存所有文件。但是，如果我删除404.html或将其重命名为其他名称，则服务工作程序将正常运行，并且将缓存所有文件。同样奇怪的是，在我的本地服务器中，服务工作者可以工作并缓存404.html，但是在firebase中失败。

为什么404.html在服务工作者缓存期间导致未捕获的错误？我该如何解决？