Steps to reproduce:

1. Set frontpage to news items, frontpageloggedin to news items and defaultfrontpageroleid to none in Administration > Front Page > Front Page settings
2. Logout and view site news items
3. Login as a student (or other non-admin user)

The student sees the following message:

Subject (hidden)
Author (hidden)
This post cannot be viewed by you, probably because you have not posted in the discussion yet.

This is obviously nonsense, as students can't post in the site news forum.

Workarounds:

Either:
Override the front page role of authenticated user and set mod/forum:viewdiscussion to allow

Or:
Set defaultfrontpageroleid to student