CartCreate mutation's BuyerIdentity does not reflect in the generated checkout link

[MoShiraz]

Hi team,
I ran into an issue while using the cartCreate graphql mutation. The BuyerIdentity email passed as an input does not reflect in the checkout link that's generated as its response.

Request: 

mutation {
  cartCreate (input: {lines : {merchandiseId: "gid://some_id", quantity:2}, buyerIdentity: {email: "test@email.com"}}) {
    cart {
      id
      checkoutUrl
      totalQuantity
      }
}

Opening the checkout link that was generated, I don't see "test@email.com" populated here.

What does 'buyerIdentity' in the input refer to here and how can I send an email to be populated in the buyer's checkout?