Searching for a work or a recording using the default indexed search is returning entries that were merged since longer than 6 hours ago. The website states:

"Search indexes are updated every 6 hours, use the direct database search if you require up to the minute correct results."

Example 1:

Indexed search of a recording

http://musicbrainz.org/search?query=Fantasia+on+a+Theme&type=recording

Click on the third entry named "Fantasia on a Theme". You'll see it has changed named to "Fantasia on a Theme by Thomas Tallis". This occurred 2011-05-18 21:00 UTC:

http://musicbrainz.org/edit/14464358

A direct search does not produce the same result, so it seems the index didn't update for more than 24 hours:

http://musicbrainz.org/search?query=Fantasia+on+a+Theme&type=recording&limit=25&direct=1

Example 2:

Indexed search of a work

http://musicbrainz.org/search?query=fourth+rendez-vous&type=work&limit=25

returns multiple entries of the same work, whilst the direct search

http://musicbrainz.org/search?query=fourth+rendez-vous&type=work&limit=25&direct=1

returns just the single merged work. This merge was closed on 2011-05-19 Thu 15:00 UTC:

http://musicbrainz.org/edit/14470460