title: Why PWA App launched from "Add to Homescreen" can't load without Internet connection?
body: <p>We have made our site (<a href="https://www.hijup.com" rel="nofollow noreferrer">https://www.hijup.com</a>) PWA ready with Add to HomeScreen capability. The app can be launched from the HomeScreen with Internet connection on. But when the connection is turned off, there is a dialog box as follow:</p>
  
  <p>"To use [my_app_name] for the first time, please connect to the Internet"</p>
  
  <p>Why does it still require Internet connection? All the JS &amp; CSS are already precached (using <code>workbox.precaching</code>) and the <code>start_url</code> has been cached with <code>networkFirst</code> strategy. Moreover, it is not the first time I launched the app (as what the dialog message suggests).</p>