Search Keywords with No Results should have a limit independent of the Site Search Keyword report #20065

At present the Search Keywords with No Results report is directly limited by the Site Search Keywords report row limit.

Only when a search keyword is present in the Site Search Keywords report is it included in the "No Results" report. This means that for sites that have a large number of Site Searches they are losing out on potentially valuable information about their "Top No Results keywords"

Had a quick look at the code. It's correct, that we are currently building only one archive for the site search reports.
The Search Keywords with No Results uses that archive by filtering out all records that had a result. So in theory the report might not even have any results if there had been more than 500 keywords with a result I guess.
Might make more sense to build two archive records, one with keywords with results and one without.