Cannot rename non-subdirectory site to subdirectory site

Here's a Hosting patch that unblocks the validation error, the migration seems to run fine, but then the site won't load, and then strange things start happening. The login link produces:

The website encountered an unexpected error. Please try again later.

aegir@aegir:~/hostmaster-7.x-3.180/sites/all/modules/hosting$ drush @site1.example.com ws --tail --full
Drupal\Core\DependencyInjection\ContainerNotInitializedException: \Drupal::$container is not initialized yet. \Drupal::setContainer() must be called with a real container. in /var/aegir/platforms/drupal_8_core/core/lib/Drupal.php on line 130 #0 /var/aegir/platforms/drupal_8_core/core/lib/Drupal.php(509): Drupal::getContainer() [...]

aegir@aegir:~/hostmaster-7.x-3.180/sites/all/modules/hosting$ drush @site1.example.com provision-verify
Changed group ownership of <code>/var/aegir/platforms/drupal_8_core/sites/site1.example.com/local.settings.php to www-data[success]
Changed permissions of <code>/var/aegir/platforms/drupal_8_core/sites/site1.example.com/local.settings.php to 440         [success]
Changed permissions of /var/aegir/platforms/drupal_8_core/sites/site1.example.com/settings.php to 640                            [success]
Generated config in write(): Drupal settings.php file (/var/aegir/platforms/drupal_8_core/sites/site1.example.com/settings.php)  [success]
Changed permissions of /var/aegir/platforms/drupal_8_core/sites/site1.example.com/settings.php to 440                            [success]
Change group ownership of /var/aegir/platforms/drupal_8_core/sites/site1.example.com/settings.php to www-data                    [success]
Changed permissions of /var/aegir/platforms/drupal_8_core/sites/site1.example.com/aegir.services.yml to 640                      [success]
Generated config in write(): Drupal aegir.services.yml file                                                                      [success]
(/var/aegir/platforms/drupal_8_core/sites/site1.example.com/aegir.services.yml)
Changed permissions of /var/aegir/platforms/drupal_8_core/sites/site1.example.com/aegir.services.yml to 440                      [success]
Change group ownership of /var/aegir/platforms/drupal_8_core/sites/site1.example.com/aegir.services.yml to www-data              [success]
Platforms path /var/aegir/platforms exists.                                                                                      [success]
Platforms ownership of /var/aegir/platforms has been changed to aegir.                                                           [success]
Platforms permissions of /var/aegir/platforms have been changed to 755.                                                          [success]
Platforms path /var/aegir/platforms is writable.                                                                                 [success]
PDOException: SQLSTATE[HY000] [1045] Access denied for user 'site1exampleco_0'@'localhost' (using password: YES) in              [error]
/var/aegir/platforms/drupal_8_core/core/lib/Drupal/Core/Database/Driver/mysql/Connection.php:417
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