If my advance search results are on multiple pages (more than 50 items), when I click on another page, the advance filtering goes away and it brings back ALL search results.
For instance, advance search "magazine" for PS1 [NA] and you get 51 results across two pages. When I click page 2, it returns all 257 results across 6 pages. The url loses it's &platform filter. I can manually add it back to the url to get the proper page. Hope this helps!
BTW Thanks for your help Matt.