failure on wixUsers.register

When we use a custom form with code, and calling register API as a click callback, the signup request itself succeeds, and new member account is created successfully, but there is a runtime error on JavaScript saying Cannot read properties of undefined. This prevents us from proceeding post-registration callbacks such as notifications.

workerLogger.js:103 Cannot read properties of undefined (reading 'status')
(anonymous) @ workerLogger.js:103
(anonymous) @ siteMembersSdkFactory.ts:223
(anonymous) @ tslib.es6.js:102
(anonymous) @ tslib.es6.js:83
a @ tslib.es6.js:73
Promise.then (async)

it seems the error comes from the code below in siteMembersSdkFactory.ts.

const data = options?.recaptchaToken
				? await register(email, password, options)
				: await withCaptchaChallengeHandler((recaptchaToken) =>
						register(email, password, { ...(options || {}), recaptchaToken })
				  )
const response = {
  status: data.status,
  ...(data.approvalToken ? { approvalToken: data.approvalToken } : {}),
}

Is this a bug from SDK, or is there a way to avoid this error?

Thanks in advance. Tom