Secret groups, discussions are visible for non members

Hello,

I have UNA 12 installed on a test environment, without modifications, and I've noticed that non members accessing the URL of the secret group can see some details of a discussion (the title, the beginning of the question, the author of the question). 

How to reproduce : go to a "secret" group you are not member of, click on the "discussions" sub menu item ( the URL is " /page/discussions-context?profile_id= ).

Expected behavior : for a private group discussions should not be visible for non members.

Note :

- When clicking on the topic to open it, the message "Access denied. This is private content." appears as expected.

- No problem for other items (posts, albums, ...) the text is marked as private.