The backend verify sub-task in drush_provision_drupal_post_provision_import() breaks site import for Drupal 8.

Note that it doesn't really break anything. You can run Enable task and the cloned/imported site will work just fine. The problem is that in drush_provision_drupal_pre_provision_verify() it fails with error:

"Drush command terminated abnormally due to an unrecoverable error. Error: Call to undefined method stdClass::getPathname() in /path/to/core/modules/system/system.module, line 877"

The line referenced here is:

$module->info = \Drupal::service('info_parser')->parse($module->getPathname());

It is located in function _system_rebuild_module_data(), which should help in further debugging.