ERROR - Megamenu - T3 & PostgreSQL

[twister65]

Prerequisites

• T3 master
• Joomla! 3.7.4
• PostgreSQL 9.5.6

Steps to reproduce the issue

• Administrator login
• Extensions -> Templates -> Styles -> t3_bs3_blank
• Click on Megamenu

Result
An error has occurred.
0 ERROR: column "gvcms_menu.language" must appear in the GROUP BY clause or be used in an aggregate function LINE 1: SELECT menutype, language ^

Comments
https://github.com/t3framework/t3/blob/master/source/plg_system_t3/includes/admin/megamenu.php
line 214 :
$query = $db->getQuery(true)
->select('menutype, language')
->from($db->quoteName('#__menu'))
->where('published = 1')
->group('menutype');
$db->setQuery($query);
$menulangs = $db->loadAssocList('menutype');