title: Symfony debug:translation shows missing translations which are already defined in bundles
body: <p>While working with symfony translations, I have overwritten a template file from one bundle and used the translation messages in project. Translation messages are defined very well according to domain (inside <code>messages.en.xlf</code>) in bundle and works fine.</p>
  <p>But when I run the command <code>php bin/console debug:translation en --only-missing</code>, I see those messages are reported missing. I have tried with other bundles too. It behaves the same for all. Whenever I use any translation message outside the bundle, It reports missing error for those translation messages.</p>
  <p>I have also tried with <code>php bin/console debug:translation en --only-missing BundleName</code> which works fine without showing any missing errors.</p>
  <ol>
  <li>Why is <code>php bin/console debug:translation en --only-missing</code> reporting these defined translation messages as <strong>Missing</strong>?</li>
  <li>Is there any possible way by which all the defined translation messages can be tracked using <code>php bin/console debug:translation</code> without any missing errors?</li>
  </ol>