The preview_url in the response of createVoiceFromPreview is null, even though it's [required]

[alexstyl]

The docs say that the response of /v1/text-to-voice/create-previews has a (required) preview_url.

However, when I run the following code, the preview_url is always null.

const response = await elevenLabsClient.textToVoice.createVoiceFromPreview({
            voice_name: name,
            voice_description: voice_description,
            generated_voice_id: voice_id
        })
response.preview_url

I think this is a bug, given the [required] label on the docs. Can you clarify?