When Content is edited, and Preview is displayed, only the first preview shows the current state of Content in setup with Varnish/Fastly - any next will show a cached response from the reverse proxy, therefore changes won't be displayed.

Steps to reproduce:
1. Clean installation of Ibexa DXP v3.3+ with Varnish
2. Create a Folder, name it Test, and click on Preview.
3. Go back to the edition form and change the name to Test 2 and click on Preview again.

Result:
The folder will be displayed with Test for a name.

Expected result:
The folder will be displayed with Test 2 for a name.