Fix #3515 Bug: Creating an invoice from a shipment links to wrong customer order

htdocs/compta/facture.php

@@ -923,7 +923,11 @@ if (empty($reshook))
 						$exp = new Expedition($db);
 						$exp->fetch($object->origin_id);
 						$exp->fetchObjectLinked();
-						if (count($exp->linkedObjectsIds['commande']) > 0) $object->linked_objects['commande'] = $exp->linkedObjectsIds['commande'][0];
+						if (count($exp->linkedObjectsIds['commande']) > 0) {
+							foreach ($exp->linkedObjectsIds['commande'] as $key => $value){
+								$object->linked_objects['commande'] = $value;
+							}
+						}
 					}
 
 					if (is_array($_POST['other_linked_objects']) && ! empty($_POST['other_linked_objects']))