Frontend cache is not updated after Content is modified in the admin panel.

Requirements:
Working Varnish setup.

Steps to reproduce:
1. Login as admin
2. Create an Article and publish it
3. Visit the Article on the frontend (keep this tab open)
4. Go back to the back office and modify any field in created Article
5. Refresh tab opened previously

Expected:
Changes made to Content are visible

Actual:
Old version of Content is still displayed