There is a error in admin/model/billing/invoice.php / application/model/billing/invoice.php in line 144 there is no check for multilang setup in the sub SQL so the should look like this:
$sql = "SELECT *, CONCAT(c.firstname, ' ', c.lastname) AS customer, i.firstname AS firstname, i.lastname AS lastname, i.company AS company, i.website AS website, i.email AS email, i.date_modified AS date_modified, (SELECT name FROM " . DB_PREFIX . "status s WHERE s.status_id = i.status_id AND s.language_id = " . (int)$this->config->get('config_language_id') . ") AS status FROM " . DB_PREFIX . "invoice i LEFT JOIN " . DB_PREFIX . "customer c ON c.customer_id = i.customer_id WHERE i.invoice_id = '" . (int)$invoice_id . "' AND i.status_id > 0";
insted
with: AND s.language_id = " . (int)$this->config->get('config_language_id') . " added
BUG invoice with multi lang
Re: BUG invoice with multi lang
please open a new issue on our git.