Definitely something weird going on.
I got results once by going to advanced, selecting check all and searching. Did it again and got nothing.
Searching over at http://community.wikia.com/wiki/Forum:Community_Central_Forum
gave old posts with similar issues, but I didn't see any definitive solutions.
I did have some trouble with search over there, if I start typing "Search" in the search box, it autosuggested a bunch of things. Clicking the search button gave no results the first time, but now seems to be working...
I didn't see anything obviously relevant in the admin panel