Exception on existing media entity import

Issue is related to #2763019 - I'm using a patch https://www.drupal.org/node/2763019#comment-11830814 to allow import existing entities. It fails for media entities.

Next exception 'Drupal\Core\Entity\EntityStorageException' with message 'SQLSTATE[23000]: Integrity constraint violation: 1062 Duplicate entry '8' for key 'PRIMARY': INSERT INTO
{media_revision} (mid, vid, langcode, revision_timestamp, revision_uid, revision_log) VALUES (:db_insert_placeholder_0, :db_insert_placeholder_1, :db_insert_placeholder_2,
:db_insert_placeholder_3, :db_insert_placeholder_4, :db_insert_placeholder_5); Array
(
[:db_insert_placeholder_0] => 8
[:db_insert_placeholder_1] => 8
[:db_insert_placeholder_2] => en
[:db_insert_placeholder_3] => 1481101100
[:db_insert_placeholder_4] => 1
[:db_insert_placeholder_5] =>
)
' in /var/www/xxx/site/web/core/lib/Drupal/Core/Entity/Sql/SqlContentEntityStorage.php:770
Stack trace:
#0 /var/www/xxx/site/web/core/lib/Drupal/Core/Entity/Entity.php(364): Drupal\Core\Entity\Sql\SqlContentEntityStorage->save(Object(Drupal\media_entity\Entity\Media))
#1 /var/www/xxx/site/web/modules/contrib/default_content/src/DefaultContentManager.php(228): Drupal\Core\Entity\Entity->save()
#2 /var/www/xxx/site/web/modules/custom/xxx/xxx_dc/xxx_dc.drush.inc(26): Drupal\default_content\DefaultContentManager->importContent('xxx_content_pa...')
#3 [internal function]: drush_xxx_dc_dim('xxx_content_pa...')
#4 /var/www/xxx/site/vendor/drush/drush/includes/command.inc(422): call_user_func_array('drush_xxx_dc_d...', Array)
#5 /var/www/xxx/site/vendor/drush/drush/includes/command.inc(231): _drush_invoke_hooks(Array, Array)
#6 [internal function]: drush_command('xxx_content_pa...')
#7 /var/www/xxx/site/vendor/drush/drush/includes/command.inc(199): call_user_func_array('drush_command', Array)
#8 /var/www/xxx/site/vendor/drush/drush/lib/Drush/Boot/BaseBoot.php(67): drush_dispatch(Array)
#9 /var/www/xxx/site/vendor/drush/drush/includes/preflight.inc(66): Drush\Boot\BaseBoot->bootstrap_and_dispatch()
#10 /var/www/xxx/site/vendor/drush/drush/drush.php(12): drush_main()
#11 {main}