This find came up in a thread in German forum about another issue with plg_system_redirect.

Steps to reproduce not-translated issue

• Activate plugin plg_system_redirect with activated setting collect_urls.
• "Hack" file plugins\system\redirect\redirect.php:
  • In line 257 add line: echo Text::_('PLG_SYSTEM_REDIRECT_ERROR_UPDATING_DATABASE');
  • Frontend: Enter a wrong url to be redirected to the error page,
  • Output at top of page PLG_SYSTEM_REDIRECT_ERROR_UPDATING_DATABASE

Expected result

PLG_SYSTEM_REDIRECT_ERROR_UPDATING_DATABASE translated to An error occurred while updating the database.

Actual result

PLG_SYSTEM_REDIRECT_ERROR_UPDATING_DATABASE not translated

Additional comments

When I set in line 42 protected $autoloadLanguage = true; instead of protected $autoloadLanguage = false; the string is translated.

Question before I provide a PR is if it is by purpose that $autoloadLanguage is false and not true?