This isn't actually unexpected right now, as there has been a problem completing the search index rebuild that we need to track down. It should resolve itself when that gets resolved, though I'll leave this open until that happens.
This is sorted now. The issue was caused by a bug in the core search index rebuild system.
(On a side note, when you limit your search to resources, by default, this will only search the resource and its description. Resource updates will not be included unless you go to the advanced resource search and enable it there. In most cases, this should make the results return more relevant results. When you search everything, then resource updates are still included.)