How can I get slugs from search that can be used to get holdings data?

Hi. I've been trying to use the search api for some time. The security ownership and institutional holdings endpoints are working fine, but when I use the search endpoint, I get a list of slugs that cannot be used to find further data from holdings endpoints - they invariably get a 404 response. I noticed that these slugs tend to be from filings from years ago. Is there a way I could use the search api to get either working slugs with preferably up-to-date data?