Found a problem in version 184.108.40.206 (2012/06/12, r491).
For some reason this installation displays articles on an article list despite they are hidden or visible. Yet, these hidden articles are not available for full-view (get 404 on them, so that works ok). It's just the article list despite other settings like pagination, number of articles or their order.
Please let me know if it's a known bug and I should make an upgrade or there is some workaround.
Made this installation in August 2012, yet discovered this problem just today... it never happened in other installations (older nor newer)
thanks in advance