Empty SEO fields when asPreview is true

[paolospag]

Hello,
I'm new to this plugin and WPGraphQL and I would like to know if it's correct that the fields are empty with asPreview or if I rather need to change something.

This is my query:

const GET_POST_BY_ID = gql`
	query PostBySlug($id: ID!, $idType: PostIdType = URI, $asPreview: Boolean = false) {
		post(id: $id, idType: $idType, asPreview: $asPreview) {
			id
			slug
			isPreview
			title(format: RENDERED)
			content(format: RENDERED)
			featuredImage {
				node {
					uri
					altText
				}
			}
		seo {
			title
			metaDesc
			metaKeywords
			breadcrumbs {
				text
				url
			}
		}
		}
	}
`

And this is the method I use to run the query:

async function getSinglePost(id, asPreview = false) {
	const idType = asPreview ? 'DATABASE_ID' : 'URI';
	const { data } = await client.query({
		query: GET_POST_BY_ID,
		variables: {
			id,
			idType,
			asPreview,
		},
	});
	return data?.post || {};
}

When the variable asPreview is set to true, some fields related to Yoast SEO are empty. In particular:

seo {
	title
	metaDesc
	metaKeywords
	breadcrumbs {
		text
		url
	}
}

Am I wrong something or is it correct that it behaves like this?