Issue #3024588: InvalidArgumentException: Invalid translation language (und) specified. in Drupal\Core\Entity\ContentEntityBase->addTranslation() (line 953 of core/lib/Drupal/Core/Entity/ContentEntityBase.php).
requested to merge issue/entity_reference_revisions-3024588:3024588-invalidargumentexception-invalid-translation into 8.x-1.x