UserAgent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/65.0.3325.162 Safari/537.36

Steps to reproduce the problem:
1. open: pinterest.com 
2. Unregister service worker, clean Application cache
3. refresh with clean cache

What is the expected behavior?
The network tools show the actual size of the "sw.js" file.

What went wrong?
The network tools show "0 B" for the service worker file. This happens for me on all kind of websites (also in my test environment) when the service worker is fetched (also on service worker updates/validation requests). Furthermore, "importScript()" calls from within the service worker file show 0B as well.

Did this work before? N/A 

Chrome version: 65.0.3325.162  Channel: stable
OS Version: 10.0
Flash Version: