Cart transform not works with line items prices if product without properties

[IvGordiichuk]

Hello. 
I have custom product where I by AJAX Cart API sent to cart properties:

_total_price: totalPrice,

_airFreightFee: airFreightFee,

GOAL - change custom product line item price and add shipping fee on checkout

I've created cart transform api extension app:
run.graphql 

query RunInput {
  cart {
    lines {
      id
      quantity
      cost {
        amountPerQuantity {
          amount
          currencyCode
        }
      }
      customId: attribute(key: "_customId") {
        value
      }
      airFreightFee: attribute(key: "_airFreightFee") {
        value
      }
      totalPrice: attribute(key: "_total_price") {
        value
      }
      merchandise {
        ... on ProductVariant {
          id
          product {
            title
          }
        }
      }
    }
  }
}

run.ts 

// src/run.ts
import type {
  RunInput,
  FunctionRunResult,
  CartOperation,
} from "../generated/api";

export function run(input: RunInput): FunctionRunResult {
  const operations: CartOperation[] = [];

  for (const line of input.cart.lines) {
    const totalPriceStr = line.totalPrice?.value;
    const airFreightFeeStr = line.airFreightFee?.value;

    if (!totalPriceStr) continue;

    const basePrice = parseFloat(totalPriceStr);
    if (isNaN(basePrice)) continue;

    const airFreightFee = parseFloat(airFreightFeeStr || "0");
    const freightTotal = !isNaN(airFreightFee) ? airFreightFee * line.quantity : 0;
    const finalPrice = (basePrice + freightTotal) / 100;

    const title = airFreightFee
      ? `${line.merchandise.product.title} (Air Freight Fee: ${(freightTotal / 100).toFixed(2)} UAH)`
      : line.merchandise.product.title;

    operations.push({
      update: {
        cartLineId: line.id,
        title,
        price: {
          adjustment: {
            fixedPricePerUnit: {
              amount: finalPrice.toFixed(2),
            },
          },
        },
      },
    });

    console.log(` Updating ${line.id} to ${finalPrice.toFixed(2)} UAH`);
  }

  return {
    operations,
  };
}

When in cart we have only custom products with properties - all works good. 
But when I add another default product - custom product prices are not changes.. and I have not errors )))

Case with custom product:

Input (STDIN)

{
  "cart": {
    "lines": [
      {
        "id": "gid://shopify/CartLine/a1a82e84-86f1-4995-9517-c88d59877344",
        "quantity": 1,
        "cost": {
          "amountPerQuantity": {
            "amount": "109.0",
            "currencyCode": "UAH"
          }
        },
        "customId": {
          "value": "custom-conf-1746618826593"
        },
        "airFreightFee": {
          "value": "10000"
        },
        "totalPrice": {
          "value": "13400"
        },
        "merchandise": {
          "id": "gid://shopify/ProductVariant/50898623037604",
          "product": {
            "title": "IP65 Mini Linear Actuator"
          }
        }
      }
    ]
  }
}

Output (STDOUT)

{
  "operations": [
    {
      "update": {
        "cartLineId": "gid://shopify/CartLine/a1a82e84-86f1-4995-9517-c88d59877344",
        "title": "IP65 Mini Linear Actuator (Air Freight Fee: 100.00 UAH)",
        "price": {
          "adjustment": {
            "fixedPricePerUnit": {
              "amount": "234.00"
            }
          }
        }
      }
    }
  ]
}

Logs (STDERR)

Updating gid://shopify/CartLine/a1a82e84-86f1-4995-9517-c88d59877344 to 234.00 UAH

 

BUT if add new not custom product 
(no errors) 

Input (STDIN)

{
  "cart": {
    "lines": [
      {
        "id": "gid://shopify/CartLine/a7fe1afd-c796-4c7e-b603-512df30aa115",
        "quantity": 1,
        "cost": {
          "amountPerQuantity": {
            "amount": "50.0",
            "currencyCode": "UAH"
          }
        },
        "customId": null,
        "airFreightFee": null,
        "totalPrice": null,
        "merchandise": {
          "id": "gid://shopify/ProductVariant/46289428709540",
          "product": {
            "title": "Gift Card"
          }
        }
      },
      {
        "id": "gid://shopify/CartLine/a1a82e84-86f1-4995-9517-c88d59877344",
        "quantity": 1,
        "cost": {
          "amountPerQuantity": {
            "amount": "109.0",
            "currencyCode": "UAH"
          }
        },
        "customId": {
          "value": "custom-conf-1746618826593"
        },
        "airFreightFee": {
          "value": "10000"
        },
        "totalPrice": {
          "value": "13400"
        },
        "merchandise": {
          "id": "gid://shopify/ProductVariant/50898623037604",
          "product": {
            "title": "IP65 Mini Linear Actuator"
          }
        }
      }
    ]
  }
}

Output (STDOUT)

{
  "operations": [
    {
      "update": {
        "cartLineId": "gid://shopify/CartLine/a1a82e84-86f1-4995-9517-c88d59877344",
        "title": "IP65 Mini Linear Actuator (Air Freight Fee: 100.00 UAH)",
        "price": {
          "adjustment": {
            "fixedPricePerUnit": {
              "amount": "234.00"
            }
          }
        }
      }
    }
  ]
}

Logs (STDERR)

 Updating gid://shopify/CartLine/a1a82e84-86f1-4995-9517-c88d59877344 to 234.00 UAH

BUT 

I have not ideas what is wrong.  Need help. Thank you.