Polyfill fails on refresh for individual images

[martinthomson]

(Using Firefox 88.)

I loaded the demo page happily. Then I opened a single image in a new tab (using right-click + "Open Image in New Tab"). This fails.

A hard reload (shift-reload) fixes the problem and shows the image, but reloading the page normally (f5, ctrl-r) shows the same error. The message in the console is:

Failed to load ‘https://kagami.github.io/avif.js/Mexico.5f45d60c.avif’. A ServiceWorker passed a promise to FetchEvent.respondWith() that rejected with ‘TypeError: can't access property "id", e is undefined’. avif-sw.js:8:856