Drupal 8 multilingual module issue

I have been trying to make the multilingual module in a 8.5.3 core Drupal site work. I have two languages in the site, English and Greek (Greek is the default language) and have translated a Story item, initially in Greek language, into English and the problem I have is that both translations of the Story article are displayed on the front page when I either click the ‘English’ link of the language switcher, or the ‘Greek’ link. 

I would appreciate any tips.

Drupal version: 


Source: https://www.drupal.org/taxonomy/term/30/feed