Look for those items which have more than 2 sales, let’s say has x sales.
If you click on the item, to see the item details, you can see that in fact it has a different number of sales, different than x (for the results page).
Caching issue as far as I’m aware. Some things update straight away, others once a day. Just as an example… if you get just one sale then that can make pretty big changes to a bunch of other things, search results, top author lists, top item lists, forum stats, badges etc. Easier to make all those changes once a day rather than real-time.