I created a CUG and added required permission, enabled authentication but it did not worked. My structure is
/content/site SAML authentication required for this path. User is added to groups available in SAML response. If user has GroupA, it is added in AEM GroupA.
Requirement particular page from /content/site should be accessible to users belonging to GroupA only
/content/site/pageA - This page should be accessible to users from GroupA only.
I tried editing pageA properties and added Authentication required, permissions for GroupA but it does not worked. Users not member of GroupA can still access pageA.