UserAgent: Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/67.0.3396.79 Safari/537.36

Steps to reproduce the problem:
1. Have serviceworker catch failed fetch request and generate response with html
2. under devtools network tab: disable cache & select offline
3. reload page receiving correct response from service worker
4. view page-source (into new tab via right click -> view page source)
5. reload original tab

What is the expected behavior?
For the tab to behave as though there is no network connection.

What went wrong?
All network fetch requests are made and passed on by chrome. The page source also shows the original page which loads on fulfilled network requests.

Did this work before? N/A 

Chrome version: 67.0.3396.79  Channel: stable
OS Version: 4.4.0-57-generic #78-Ubuntu x86_64
Flash Version: 

This is all the serviceWorker code minus the response body. It forwards all requests from/for the page and creates response, containing simple html, if request fails. 

self.addEventListener("fetch", function(event) {
  event.respondWith(
    fetch(event.request).catch(function() {
      return new Response(
        responseContent,
        {headers: {"Content-Type": "text/html"}}
      );
    })
  );
});
 

Deleted: Screenshot from 2018-06-12 00-57-24.png 192 KB

	Screenshot from 2018-06-12 00-57-24.png 192 KB View Download