Ash Framework: Magic Link Auth behavior (p121)

You don’t see the warning in your logs? Like

Did you restart your dev server after changing the debug config in dev.exs?

And yes, by default registration is enabled for magic links, so entering a non-existent email address will send a link to sign in and create that account. You can disable this in your magic_link config in your User resource, by setting registration_enabled? false.