title: Error : The "kernel" service is synthetic, it needs to be set at boot time before it can be used
body: <p>In our production website, I caught errors with sentry.io. </p>
  
  <p>Since few month I have about 50 time the same error per day, but I never be able to reproduce it myself in local, preproduction, or even in production. </p>
  
  <p>I have no clue what could throw that. I never had a client that reported me this error.</p>
  
  <p>Does anyone knows what it could be?</p>
  
  <pre><code>ErrorException: Uncaught Symfony\Component\DependencyInjection\Exception\ServiceNotFoundException: The "kernel" service is synthetic, it needs to be set at boot time before it can be used. in /mnt/www/project/vendor/symfony/symfony/src/Symfony/Component/DependencyInjection/Container.php:334
  Stack trace:
  #0 /mnt/www/project/app/cache/prod/Container2xhx4bk/appProdProjectContainer.php(11988): Symfony\Component\DependencyInjection\Container-&gt;get('kernel')
  #1 /mnt/www/project/app/cache/prod/Container2xhx4bk/appProdProjectContainer.php(12085): Container2xhx4bk\appProdProjectContainer-&gt;getTemplating_LocatorService()
  #2 /mnt/www/project/app/cache/prod/Container2xhx4bk/appProdProjectContainer.php(9670): Container2xhx4bk\appProdProjectContainer-&gt;getTwig_LoaderService()
  #3 /mnt/www/project/app/cache/prod/Container2xhx4bk/appProdProjectContainer.php(9660): Container2xhx4bk\appProdProjectContainer-&gt;getTwigService()
  #4 /mnt/www/project/ap
  #1 vendor/symfony/symfony/src/Symfony/Component/DependencyInjection/Container.php(334): handleFatalError
  </code></pre>