Dear Gailhou Christophe
In this case, please open modules\mod_yt_sobi2megaslider\assets\libsmegaslider.php file, find sql query to change:
$query = "SELECT si.title, si.itemid, si.icon, si.image,si.last_update, sfd.data_txt
FROM `#__sobi2_item` si
LEFT JOIN #__sobi2_fields_data sfd ON sfd.itemid = si.itemid
LEFT JOIN #__sobi2_language sl ON (sl.fieldid = sfd.fieldid AND sl.langKey = 'field_description')
WHERE `published` = 1 AND (`publish_down` > '{$now}' OR `publish_down` = '{$config->nullDate}') AND sl.fieldid <> ''";
Thanks