Steps to reproduce:
1. Add a site role
2. Define permissions for site role > Site Admin > Pages > Site Pages > flag Manage Pages > Click Save
3. Add a site and a public page to the site
4. Add a user
5. Assign site and site role to user
6. Log out and log in as user
7. Navigate to Site
8. Try to add a portlet
User is able to add portlets.
User is unable to add any portlets.
In ee-6.2.x, the user is able to add any portlet to a site page with the site role permission 'Manage Pages' assigned.