When a page varies according to the logged in user's segments, the http cache for it may not vary depending on the segments.

The context hash depends on the roles of the user, not on its segments

Test done (with varnish enabled):

• user A, with segment A, from group Members
• user B, with segment B, from group Members
• page with a targeting block that shows Content A to segment A, and Content B to Segmet B
• log in to the frontend as user A, visit page, you see Content A
• log out, log in as user B, visit the page, you will see Content A instead of Content B