Optional section is not cached correctly

[johanarnor]

Hi! I've an issue where assets in the optional section are not present in the cache after a new build. The caches option is configured (heavily simplified) like this:

caches: {
  main: ['index.html', 'app.js'],
  optional: ['app.css']
},

Steps to reproduce:

• Load the site and see that all 3 assets are cached.
• Make a new build (ensure that app.css is unchanged) and apply the update. Only index.html and app.js are now present in the cache.
• Go offline and reload the site - app.css is not loaded since it's not in the cache.

Is it possible to "transfer" the previously cached version of app.css to the new cache, since the hash is same? Or is there some reason that it doesn't work as I thought it would? Or maybe I've just messed up my config somehow...

Any help would be much appreciated!