[ic] Search box not returning all matches

[Interchange user]

I have a weird problem whereby something typed into the search box doesn't 
return all the items that it should. It seems to be listing only items that 
have been in the database (MySQL) for a long time (i.e. several months). 
Things that I've added more recently aren't returned in the results.

This was happening a while ago with some items, but they have since began 
appearing in the results.

Can anyone tell me what's up?