CartTransform/Bundles not working with Gift Cards

Functions
1

I am trying to get Gift Cards to apply towards bundles I create via a Cart Transform Function.

The gift card applies fine on the same variants as individual line items in my cart.
But when a bundle is created from them (lineExpand operation) I get the generic error in checkout

Your gift card can no longer be applied to this order and has been removed

Here is the expand operation for reference:

const {id: cartLineId, merchandise, cost} = lineItem
const operation = {
  lineExpand:{
    cartLineId,
    title: 'Bundle of two things',
    expandedCartItems: [
      {
        merchandiseId: merchandise.id,
        quantity: 1,
        price: {
          adjustment: {
            fixedPricePerUnit: {amount: 0.0} // Adjust price to zero
          }
        }
      },
      {
        merchandiseId: specialFeeVariantId,
        quantity: 1,
        price: {
          adjustment: {
            fixedPricePerUnit: {
              amount: cost.amountPerQuantity.amount // full cost on this lineitem
            }
          }
        }
      },
    ],
  }
}