There are reports from several sources including WebmasterWorld that Google is having a tough time mapping the proper URLs with the associated page titles for those URLs.
One report says that Google is treating searches for portal A on a subdirectory of a governmental site all wrong. So a search for a keyword that would trigger a result from portal A on subdirectory A, would in fact return a result from subdirectory B, with a page title from subdirectory C. I.e. A search that would typically return a page title and URL from domain.com/subdirectoryA/ is returning a URL from domain.com/subdirectoryB/ and a page title from domain.com/subdirectoryC.
Other reports are saying that on some [site:www.domain.com keyword] command searches, Google is returning results from totally different domains, outside of the restricted domain you entered.
I am not sure how wide scale the issue is and I have no hard examples that I can provide, due to WebmasterWorld's guidelines - but there are several reports on this behavior.
Forum discussion at WebmasterWorld.