(I'm moving a bunch of third-party details over from https://bugs.chromium.org/p/chromium/issues/detail?id=810469, as that issue is marked WontFix.)

As per the more recent reports, this appears to be cropping up on Windows 10 running M65.

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The initial report:

UserAgent: Mozilla/5.0 (X11; Linux x86_64; rv:58.0) Gecko/20100101 Firefox/58.0

Steps to reproduce the problem:
1. Go to https://morning-landmine.glitch.me/
2. Open the console and notice the logs and errors

Source Code: https://glitch.com/edit/#!/morning-landmine?path=views/index.html:30:6

What is the expected behavior?
The "module.js" file should be cachable in the window and the service worker.

What went wrong?
The service worker throws an error in Chrome 65 "Uncaught (in promise) SyntaxError: Unexpected token export".

(Not this is just **caching** the file - not running it)

Did this work before? N/A 

Chrome version: 65.0.3325.51 (Official Build) dev (64-bit)  Channel: n/a
OS Version: 
Flash Version:


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Some more recent reports:

Same problem here, with a GitHub Pages hosting, and the Workbox service worker library:

https://helloesm.hwalab.com/

Repository source code:

https://github.com/hwalab/helloesm

Google Chrome 65.0.3325.181 (Official Build) (64-bit) on Windows 10 Home 10.0.16299 Build 16299


app.js:6 Uncaught (in promise) SyntaxError: Unexpected identifier
    at Object.<anonymous> (workbox-core.prod.js:1)
    at Generator.next (<anonymous>)
    at n (workbox-core.prod.js:1)
    at workbox-core.prod.js:1

The service worker fails to activate ("is redundant"), and the Chrome Lighthouse audit tool reports that "user will not be prompted to install the Web App".

On Chrome 65.0.3325.109 on Android 7.0, the Add to Home screen option, which used to install the PWA in the past, after refresh now it only offers to add it as a simple shortcut.

More details and screenshots in this Workbox issue comment:
https://github.com/GoogleChrome/workbox/issues/1433#issuecomment-381656479