Estimated when sending to print instead of the list to be printed appears the main page for mobile version.

https://www.buscobarato.cl/en-venta/animales/ejemplo-de-anuncio_i1

solved,

in ..../oc-content/plugins/print_ad/index.php   search

$path = osc_base_url() . 'oc-content/plugins/print_ad/';


and replace with

    $path = osc_ajax_plugin_url('print_ad/');


Best regards