Let's say there is eZ Platform site on Platform.sh. Own domain is used to access the admin. So site has following domains:

• https://project.com for front-end
• https://admin.project.com for admin UI

Front-end (https://project.com) is served by Varnish, but admin is not:

// .platform/routes.yaml
https://project.com:
    type: upstream
    upstream: varnish:http
https://admin.project.com:
    type: upstream
    upstream: app:http

When you edit/publish some content in admin UI (https://admin.project.com), it is expected that its Varnish cache will be cleared. But actually, the Varnish cache is not cleared.