CAUGHT YOU!
Something just tried to set the cookie to 'en'.
The culprit is listed below (read from bottom up):

#0 /home/www/restodata.ca/includes/__language_handler.php(232): setLanguageCookie()
#1 /home/www/restodata.ca/includes/settings_MTL.php(181): require_once('...')
#2 /home/www/restodata.ca/includes/settings.php(469): include('...')
#3 /home/www/restodata.ca/resto/index.php(2): include_once('...')