title: Django compress error: Invalid input of type: 'CacheKey'
body: <p>We suddenly started getting this issue when compressing django static files on production servers. Ubuntu 16.04, Python 3.x, Django 1.11. I am using an ansible-playbook to deploy.</p>
  
  <p>The error is as follows:</p>
  
  <p><code>CommandError: An error occurred during rendering /chalktalk/app/chalktalk-react-40/chalktalk-react-40/chalktalk/apps/exams/templates/exams/section-edit.html: Invalid input of type: 'CacheKey'. Convert to a byte, string or number first.</code></p>
  
  <p>It doesn't seem to be an issue in one of the static files but a general issue. Every time we run it, we get a different file.</p>
  
  <p>I was looking for any clues on google and nothing shows up with the same error.</p>