I think this is a bug by design. At a really high level (and without getting into the intricacies of why) , the way lists of content in Clearspace is architected is that we first do a SQL query to get content which returns a list of ID's, then we get a content object (the document, message or blog post, usually from cache) and then everything passes through a proxy layer which checks the permissions on each one of the objects in the list. The bug by design is that the pagination is all based off the number of results in the SQL query, while the actual number of items you see on the page is determined by the permissions you have.
Long story short: I'm not sure that there's anything we're going to do about it in the near-time since the bug only manifests itself if you have a small number of documents / discussions / blog posts. That help?
Actually, I think the problem is that the "more" link shows up regardless of the number of documents you have. On my test instance, I only have 10 items showing up. I only have 10 items total in my system (it is a test instance). The more link should only display if there are more than 25 documents in the list.
Version 1.1 of Clearspace offers the standard pagination links (1,2,3 Previous...Next). I don't have a test instance of 1.1 yet (not released until the end of the month), so can't verify that this is fixed. Please let me know if this happens on 1.1 as well.