If the PWA fails to cache all its assets on first load, it should later fetch (and cache) any resources needed if it is online. But it doesn't always seem to do this. For example, with the darkreader.min.js plugin, I have seen a few cases of it failing to load as part of the PWA, and then refusing to load subsequently. It just silently fails and the user is left wondering why dark mode is not responding.

What should happen is that resources are fetched from the server whenever needed if they are not cached, as this is part of the PWA specification (fallback to online version). Needs debugging, but it is difficult to reproduce.