Currently, if you are on any page later than the first of a found set, and you create a new search, the system (for some reason I cannot fathom) retains the current set list page and attempts to return you there. As a result, if the new set has fewer pages than the one you were working on, the new set appears to be empty even if it is not.
For example, let's say you pull a found set that spans 8 SERPs and you're viewing page 6 of that set. You then run a new search which returns only 1 page of results. What you're then looking at is a blank set which appears to be empty. But it's not. To get to the results, you have to click on the Page 1 icon to move from a non-existent 6th set page to get to the results of your new search.
There is absolutely no reason for the system to remember what SERP page you are on and try to return you there when initiating a new search. All new search results should move you to the first record of the first page of results by default.