That search function seems a bit temperamental for me as well. Seems like it gives good results when you first type something in, but as soon as you start scrolling down the page it throws everything back in.
But yeah, no idea why that one is in the results, but I also noticed that entry 381 is misnumbered sequentially, it should be 579 as it falls between 578 and 580. Not sure who owns that site, I don't see a way to contact them. I announced the sequence issue on the board, but nobody spoke up at the time.