I have WP 3.8.1 running with Global Site Search (and Post Indexer) installed. Within Post Indexer I have "Post" and "Page" as types of posts to index. I did a Rebuild and everything showed up beautifully and was all "findable" in a search. Then when I added or updated a post or page only the last pages/posts updated are found in a search -- I do not mean the Stats, I mean the search results. I would then do another Rebuild on the Indexer plugin and the same thing. Everything shows up in as available for searching and as soon as there is any update on any Blog site only the new or updated page/post is searchable.