`SignupOptions` field `phone` does not work for attaching phone number to user object

[Amund-Fremming]

Im currently trying to create a custom signup flow with ACUL. Im using the SignupOptions interface to pass data to auth0, but the field phone is not working. I have also tried to add custom fields as phoneNumber and phone_number but nothing seems to set the users phone number on the auth0 user object.

Im using this interface provided by the SDK:

export interface SignupOptions {
    email?: string;
    username?: string;
    phone?: string;
    captcha?: string;
    [key: string]: string | number | boolean | undefined;
}

This is the payload printed before its sendt:

Object { email: "``amund.fremming+test10@gmail.com``", username: "", phone: "41387142", captcha: "", given_name: "Amund", family_name: "Fremming" }

And this is the auth0 user object after user creation:

{
    “user_id”: “auth0|6a0fff6efd418ca80717c92e”,
    “created_at”: “2026-05-22T07:02:06.203Z”,
    “email”: “``amund.fremming+test10@gmail.com``”,
    “email_verified”: false,
    “identities”: [
        {
            “connection”: “Username-Password-Authentication”,
            “provider”: “auth0”,
            “user_id”: “6a0fff6efd418ca80717c92e”,
            “isSocial”: false
        }
    ],
    “name”: “``amund.fremming+test10@gmail.com``”,
    “nickname”: “amund.fremming+test10”,
    “picture”: “``https://s.gravatar.com/avatar/6ba82f81c0780dddecea0636dbead9d3?s=480&r=pg&d=https%3A%2F%2Fcdn.auth0.com%2Favatars%2Fam.png”``,
    “updated_at”: “2026-05-22T07:02:06.203Z”,
    “user_metadata”: {},
    “app_metadata”: {
        “given_name”: “Amund”,
        “family_name”: “Fremming”
    },
    “last_ip”: “109.74.183.126”,
    “last_login”: “2026-05-22T07:02:06.196Z”,
    “logins_count”: 1,
   “guardian_authenticators”:,
   “blocked_for”:,
   “passkeys”:
}