A bit of context would help answer your question.

you do a search and then hit your browser’s back button to do another search. You need to completely reload the search page or it won’t work.

If you click the “go back” link it will take you back to the search page and properly reload the page, and your next search will work.

At least I think that’s it... Elad would be able to give you a better explanation.

If I reload that, I get the warning "... the software cannot verify the legitimacy of the search attempt...."

Thanks for looking into this small problem.