"www" appended to beginning of URL of site with existing subdomain unnecessarily, causing failure

error-0x29A

search for "Arcane Vestments"
first result is listed as arcanevestments.bigcartel.com
when visiting, link is turned into www.arcanevestments.bigcartel.com by Kagi I assume (not by the site) and fails
if i visit the original URL (arcanevestments.bigcartel.com) manually in the browser, it works fine and does not try to append a www, but clicking the result link from Kagi does
other search engines do not append the www and thus link to the site successfully

Original URL already has a subdomain and even if it didn't, not all sites redirect www to non and vice versa, so I think modifying the URL at all seems like a bad idea?

Have the original (and shown) URL of the site in the results be the URL that is actually visited in the browser, not a changed URL (for instance, with an extra www. prefix, as in this case)

z64

error-0x29A Nothing on our end here, this is exactly as it comes from upstream indexes unfortunately. This type of thing (bugs in upstream indexes, dead links being served, bad SEO, ...) is something hard for us to address holistically without full control of the data - which is partly why we give users the ability to block/raise domains and to patch up URLs with Redirects that get "stuck" in the indexes that we pull from.

(Assuming there isn't an epidemic of such issues to inform something actionable)