The deploy preview link now points at a host that serves it
Every deploy without a custom domain showed a preview link that returned 404, because the link named the edge node rather than the control plane. Deploys with a domain were unaffected, which is why it went unnoticed.
After a deploy, the build panel offers a link to preview what you just published. Unless your project had a custom domain, that link returned a 404.
The preview URL is served by the control plane, but the panel was building it onto the edge node’s hostname, which doesn’t answer that route. A deploy with a custom domain never used the fallback at all, so it worked — which is exactly why this survived unnoticed. The people best placed to spot it were the ones least likely to see it.
The panel now names the right host. Where it can’t determine one, it shows no link rather than one that fails.