If you do a search in the Rig Exchange, the results show up - let's say there's 3 pages of results. You navigate to page 3. You do another search, which returns only 2 pages of results. The search appears to return no results, but it looks like what's happening is you are still on page 3...since there is no page 3 anymore, you don't see any results. But you can see the pages listed at the bottom, and if you click page 1 or 2, then you see the results.
It would seem much more user friendly to return to page 1 when a new search is submitted, rather than leave the page number set to an invalid option. This is even the case if it's not an invalid page number. Anytime I do a search on any piece of software I'm expecting to return to the top of the result set.