I have similar problem, translation is fine and i check the where this variable is defined and i go to file SHOP/module/ps_wirepayment/views/templates/hook/payment_return.tpl and in the line 22
{l s='Your order on %s is complete.' sprintf=[$shop_name] d='Modules.Wirepayment.Shop'}<br/>
i change $shop_name to this $shop.name and it's working