This is the second site I've noticed this on - in both cases, the site is running PHP 7.1.32, as reported on the Drupal system status page.
CiviCRM requires PHP 7.0.0+. The web server is running PHP 5.6.40. Drush command terminated abnormally due to an unrecoverable error.
The Drush commands seem to execute, though. The commands have nothing to do with Civi, BTW - these are standard install/enable Drush commands.
See related issue at:
Any guidance appreciated...