title: Vim switching between highlighted and non-highlighted syntax
body: <p>Here is my problem :</p>
  
  <ol>
  <li>I open a file with <code>vim /etc/file.toml</code>, it's syntax-highlighted </li>
  <li>I edit it and save it</li>
  <li>Sometimes (not everytimes), when I re-open the file later, it's not syntax-highlighted anymore.</li>
  </ol>
  
  <p>Anybody has an idea of how to fix this issue ? Cache problem ?</p>
  
  <p>Note : that this problem occurs with almost every file extension, I do not switch user (always root).</p>