• Files stored in the Library at Users/Public location can be accessed anonymously.  However, It could be seen requesting for an authentication when viewing the analysis on the Web Player.
• Folders within Public Folder seem to have the right permissions. i.e the "Public Access" group having the Browse/Access permissions.

TIBCO Cloud Spotfire

Consider there is a successful authentication made into the Spotfire Cloud in the current browser session followed by a logout. Now on browsing the analysis file URL (stored in the Public folder) user is prompted for login which seems to contradict the idea of anonymous access to the files in the Public folder.

This behaviour is a result of certain changes made in Spotfire 11.1.  After a user has authenticated, a cookie is set that prevents anonymous authentication if the session times out. This cookie is (by default) cleared if the browser is closed, or when explicitly logging out (the latter however doesn't work in TIBCO Cloud Spotfire since the logout there is handled by the Global Navigation Header and Trop, and not by Spotfire).
So, this will only affect users that have previously logged in (and haven't restarted the browser since then). 

So ideally this anonymous access shouldn't affect the users than can just sign in. These users can sign in and view the reports in the current browser session. 

NOTE:
For the rest of the users who have no accounts registered and are public users can always view the analysis reports on the web without any need for authentication. These users won't face such a scenario.
 
 

Files stored in Library at Users/Public location can be accessed anonymously. However, a request for authentication could be seen when viewing the analysis on the Web Player.

TIBCO Cloud Spotfire:
https://docs.tibco.com/products/tibco-cloud-spotfire