My domain islandwrites.com has nameservers delegated to Vercel (ns1.vercel-dns.com / ns2.vercel-dns.com), and the Vercel API (vercel dns ls) shows the correct records: ALIAS, CAA, and www CNAME to cname.vercel-dns.com.
However, querying the authoritative Vercel nameservers directly returns stale Squarespace records:
dig @ns1.vercel-dns.com islandwrites.com A +short
Returns 198.185.x / 198.49.x (Squarespace IPs)
dig @ns1.vercel-dns.com www.islandwrites.com CNAME +short
Returns ext-sq.squarespace.com
This is an infrastructure-side mismatch — the authoritative zone needs to be reconciled/purged to match the API state. Requesting Vercel DNS engineering assistance.